diff --git a/crates/gc-formats/src/occlusion.rs b/crates/gc-formats/src/occlusion.rs
index 8074370..d176999 100644
--- a/crates/gc-formats/src/occlusion.rs
+++ b/crates/gc-formats/src/occlusion.rs
@@ -68,11 +68,15 @@ impl Occlusion {
 
     /// Is an object with these occlusion bits visible from this mask?
     ///
-    /// The bits are `byte << 8 | 1 << bit`, folded at level load. The test is
-    /// the game's: `mask[byte] & bit == 0` means skip.
+    /// The bits are `byte << 8 | 1 << bit`, folded at level load: the high
+    /// byte selects the mask byte and the low byte is *already* the shifted
+    /// bit, not an index. Shifting the low byte again is both wrong and a
+    /// panic, since any byte above 8 overflows a `u8` shift.
+    ///
+    /// The test is the game's: `mask[byte] & bit == 0` means skip.
     pub fn visible(&self, mask_index: u16, bits: u16) -> bool {
         let byte = (bits >> 8) as usize;
-        let bit = 1u8 << (bits & 0xff);
+        let bit = (bits & 0xff) as u8;
         self.masks
             .get(mask_index as usize)
             .is_some_and(|m| byte < MASK_BYTES && m[byte] & bit != 0)