diff --git a/src/labels/mod.rs b/src/labels/mod.rs
index ea86848..55b9445 100644
--- a/src/labels/mod.rs
+++ b/src/labels/mod.rs
@@ -1 +1,2 @@
 pub mod parse;
+pub mod sanitize;
diff --git a/src/labels/parse.rs b/src/labels/parse.rs
index df47083..65567ea 100644
--- a/src/labels/parse.rs
+++ b/src/labels/parse.rs
@@ -15,10 +15,11 @@ enum Chunk {
     Reference(LabelName),
 }
 
-struct LabelName {
-    namespace: CompactString,
-    name: CompactString,
-    local: Option<CompactString>,
+#[derive(Clone, Debug)]
+pub struct LabelName {
+    pub namespace: Option<CompactString>,
+    pub name: CompactString,
+    pub local: Option<CompactString>,
 }
 
 fn parse_stat_labels(stat: &Stat) -> ParsedStat {
@@ -40,14 +41,14 @@ fn parse_stat_labels(stat: &Stat) -> ParsedStat {
             result.push(Chunk::Verbatim(code[offset..start].into()))
         }
         let mut label = LabelName {
-            namespace: CompactString::with_capacity(0),
+            namespace: None,
             name: CompactString::with_capacity(0),
             local: None,
         };
         for child in cap.children() {
             match child.kind() {
                 Tag::Namespace => {
-                    label.namespace = child.text().into();
+                    label.namespace = Some(child.text().into());
                 }
                 Tag::Global => {
                     label.name = child.text().into();
diff --git a/src/labels/sanitize.rs b/src/labels/sanitize.rs
new file mode 100644
index 0000000..70a3199
--- /dev/null
+++ b/src/labels/sanitize.rs
@@ -0,0 +1,303 @@
+use std::collections::{HashMap, HashSet};
+
+use compact_str::CompactString;
+
+use super::parse::LabelName;
+
+#[derive(PartialEq, Eq, Hash)]
+struct LabelId(CompactString);
+
+impl LabelId {
+    fn new(label: &LabelName) -> Self {
+        let mut result = CompactString::with_capacity(0);
+        if let Some(namespace) = &label.namespace {
+            result.push_str(&namespace);
+            result.push('~');
+        }
+        result.push_str(&label.name);
+        if let Some(local) = &label.local {
+            result.push('.');
+            result.push_str(&local);
+        }
+        result.make_ascii_lowercase();
+        LabelId(result)
+    }
+}
+
+pub struct Registry {
+    label_transforms: HashMap<LabelId, Transform>,
+    existing: HashSet<CompactString>,
+}
+
+enum Transform {
+    Preferred,
+    FilteredWithSuffix(CompactString),
+}
+
+impl Transform {
+    fn apply(&self, label: &LabelName) -> CompactString {
+        match self {
+            Transform::Preferred => Registry::preferred_name(label),
+            Transform::FilteredWithSuffix(suffix) => {
+                let mut result = Registry::preferred_name(label);
+                result = Registry::filter_label_chars(&result);
+                result.push_str(&suffix);
+                result
+            }
+        }
+    }
+}
+
+impl Registry {
+    pub fn new() -> Self {
+        let builtin_labels = ["bombed", "energize", "shot", "thud", "touch"];
+        let mut label_transforms = HashMap::new();
+        let mut existing = HashSet::new();
+        for name in builtin_labels {
+            let cs = CompactString::new(name);
+            label_transforms.insert(LabelId(cs.clone()), Transform::Preferred);
+            existing.insert(cs);
+        }
+        Self {
+            label_transforms,
+            existing,
+        }
+    }
+
+    pub fn sanitize(&mut self, label: &LabelName) -> CompactString {
+        // Use existing sanitization if one exists
+        let id = LabelId::new(label);
+        if let Some(transform) = self.label_transforms.get(&id) {
+            return transform.apply(&label);
+        }
+
+        // Try to use label's preferred name as-is
+        let preferred = Transform::Preferred.apply(label);
+        if Registry::is_valid_label(&preferred) {
+            let key = preferred.to_ascii_lowercase();
+            if !self.existing.contains(&key) {
+                self.label_transforms.insert(id, Transform::Preferred);
+                self.existing.insert(key);
+                return preferred;
+            }
+        }
+
+        // Generate a new name by appending suffixes
+        let base = Registry::filter_label_chars(&preferred);
+        let base_len = base.len();
+        let mut candidate = base;
+        let mut suffix = CompactString::with_capacity(0);
+        loop {
+            candidate.push_str(&suffix);
+            let key = candidate.to_ascii_lowercase();
+            if !self.existing.contains(&key) {
+                self.label_transforms
+                    .insert(id, Transform::FilteredWithSuffix(suffix));
+                self.existing.insert(key);
+                break;
+            } else {
+                candidate.truncate(base_len);
+                increment(&mut suffix);
+            }
+        }
+        candidate
+    }
+
+    fn preferred_name(label: &LabelName) -> CompactString {
+        let src = if let Some(local) = &label.local {
+            local
+        } else {
+            &label.name
+        };
+        CompactString::new(src)
+    }
+
+    fn is_valid_label(s: &CompactString) -> bool {
+        if s.len() == 0 {
+            return false;
+        }
+        let (most, last) = s.split_at(s.len() - 1);
+        if !most.chars().all(|c| c == '_' || c.is_ascii_alphabetic()) {
+            return false;
+        }
+        last.chars().all(|c| c == '_' || c.is_ascii_alphanumeric())
+    }
+
+    fn filter_label_chars(s: &CompactString) -> CompactString {
+        let mut result = CompactString::with_capacity(0);
+        let mut run_of_digits = false;
+        for c in s.chars() {
+            if c.is_ascii_digit() {
+                if !run_of_digits {
+                    result.push('_');
+                    run_of_digits = true;
+                }
+            } else {
+                result.push(c);
+                run_of_digits = false;
+            }
+        }
+        result
+    }
+}
+
+/// Increments a string through label-safe characters.
+/// Characters loop through underscore and the letters a-z.
+/// Additionally, the final character is allowed to loop through 0-9.
+fn increment(s: &mut CompactString) {
+    let original_len = s.len();
+
+    // Find a character we can increment without carry
+    dbg!(&s);
+    let mut last_char = s.pop();
+    while !(last_char == None || last_char != Some('z')) {
+        last_char = s.pop();
+    }
+    dbg!(s.len(), last_char);
+
+    if let Some(c) = last_char {
+        // Increment character in order: 0-9, then _, then a-z
+        let incremented = match c {
+            '0'..'9' | 'a'..'z' => (c as u8 + 1) as char,
+            '9' => '_',
+            '_' => 'a',
+            _ => unreachable!(),
+        };
+        s.push(incremented);
+
+        // Pad to original length, like "___0"
+        while s.len() < original_len {
+            let is_last = s.len() == original_len - 1;
+            s.push(if is_last { '0' } else { '_' });
+        }
+    } else {
+        // We reached maximum value for the string: everything rolls over
+        for _ in 0..original_len {
+            s.push('_');
+        }
+        s.push('0');
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use core::num;
+    use std::collections::HashSet;
+
+    use compact_str::CompactString;
+    use insta::{assert_debug_snapshot, assert_snapshot};
+
+    use crate::labels::{parse::LabelName, sanitize::Registry};
+
+    use super::increment;
+
+    #[test]
+    fn test_increment_100() {
+        let mut rows = vec![];
+        let mut ctr = CompactString::new("");
+        for _ in 0..10 {
+            let mut row = vec![];
+            for _ in 0..10 {
+                increment(&mut ctr);
+                row.push(ctr.to_string());
+            }
+            rows.push(row.join(", "));
+        }
+        let result = rows.join("\n");
+        assert_snapshot!(result, @r"
+        0, 1, 2, 3, 4, 5, 6, 7, 8, 9
+        _, a, b, c, d, e, f, g, h, i
+        j, k, l, m, n, o, p, q, r, s
+        t, u, v, w, x, y, z, _0, _1, _2
+        _3, _4, _5, _6, _7, _8, _9, __, _a, _b
+        _c, _d, _e, _f, _g, _h, _i, _j, _k, _l
+        _m, _n, _o, _p, _q, _r, _s, _t, _u, _v
+        _w, _x, _y, _z, a0, a1, a2, a3, a4, a5
+        a6, a7, a8, a9, a_, aa, ab, ac, ad, ae
+        af, ag, ah, ai, aj, ak, al, am, an, ao
+        ");
+    }
+
+    #[test]
+    fn test_increment_all_len_3() {
+        // Most chars are alphabetic or underscore (26 + 1 = 27).
+        // Last char can include digits (27 + 10 = 37).
+        let num_labels = 37 + 27 * 37 + 27 * 27 * 37; // 1 char + 2 chars + 3 chars
+        let mut ctr = CompactString::new("");
+        let mut seen = HashSet::with_capacity(num_labels);
+        for _ in 0..num_labels {
+            increment(&mut ctr);
+            assert!(Registry::is_valid_label(&ctr));
+            assert!(!seen.contains(&ctr));
+            assert!(ctr.len() <= 3);
+            seen.insert(ctr.clone());
+        }
+
+        // Make sure we exhausted all possible length-3 labels
+        increment(&mut ctr);
+        assert_eq!(ctr.len(), 4);
+    }
+
+    #[test]
+    fn test_sanitize_simple() {
+        let mut reg = Registry::new();
+        let mut results = vec![];
+        let simple = |s: &str| -> LabelName {
+            LabelName {
+                name: s.into(),
+                namespace: None,
+                local: None,
+            }
+        };
+        let full = |ns: &str, name: &str, local: &str| -> LabelName {
+            let mut result = LabelName {
+                namespace: None,
+                name: name.into(),
+                local: None,
+            };
+            if ns.len() > 0 {
+                result.namespace = Some(ns.into());
+            }
+            if local.len() > 0 {
+                result.local = Some(local.into());
+            }
+            result
+        };
+        let inputs = [
+            simple("foo"),
+            full("alt", "foo", ""),
+            full("", "foo", "thisloop"),
+            full("", "foo", "thatloop"),
+            full("", "bar", "thisloop"),
+            full("", "bar", "thatloop"),
+            simple("bar1"),
+            simple("bar2"),
+            simple("bar123"),
+            simple("BAR123"),
+            simple("bar456"),
+            simple("BAR456"),
+            simple("foo2bar"),
+        ];
+        for label in inputs {
+            let sanitized = reg.sanitize(&label);
+            assert_eq!(sanitized, reg.sanitize(&label));
+            results.push(format!("{:?} => {}", &label, sanitized));
+        }
+        let result = results.join("\n");
+        assert_snapshot!(result, @r#"
+        LabelName { namespace: None, name: "foo", local: None } => foo
+        LabelName { namespace: Some("alt"), name: "foo", local: None } => foo0
+        LabelName { namespace: None, name: "foo", local: Some("thisloop") } => thisloop
+        LabelName { namespace: None, name: "foo", local: Some("thatloop") } => thatloop
+        LabelName { namespace: None, name: "bar", local: Some("thisloop") } => thisloop0
+        LabelName { namespace: None, name: "bar", local: Some("thatloop") } => thatloop0
+        LabelName { namespace: None, name: "bar1", local: None } => bar1
+        LabelName { namespace: None, name: "bar2", local: None } => bar2
+        LabelName { namespace: None, name: "bar123", local: None } => bar_
+        LabelName { namespace: None, name: "BAR123", local: None } => BAR_
+        LabelName { namespace: None, name: "bar456", local: None } => bar_0
+        LabelName { namespace: None, name: "BAR456", local: None } => BAR_0
+        LabelName { namespace: None, name: "foo2bar", local: None } => foo_bar
+        "#);
+    }
+}