diff --git a/src/critter.cc b/src/critter.cc
index 50fa5f3..c576549 100644
--- a/src/critter.cc
+++ b/src/critter.cc
@@ -1414,4 +1414,22 @@ void critter_flag_set(int pid, int flag)
     proto->critter.data.flags |= flag;
 }
 
+// 0x42E71C
+void critter_flag_unset(int pid, int flag)
+{
+    Proto* proto;
+
+    if (pid == -1) {
+        return;
+    }
+
+    if (PID_TYPE(pid) != OBJ_TYPE_CRITTER) {
+        return;
+    }
+
+    protoGetProto(pid, &proto);
+
+    proto->critter.data.flags &= ~flag;
+}
+
 } // namespace fallout
diff --git a/src/critter.h b/src/critter.h
index ea83f8d..ef4f873 100644
--- a/src/critter.h
+++ b/src/critter.h
@@ -71,6 +71,7 @@ bool critterIsEncumbered(Object* critter);
 bool critterIsFleeing(Object* a1);
 bool _critter_flag_check(int pid, int flag);
 void critter_flag_set(int pid, int flag);
+void critter_flag_unset(int pid, int flag);
 
 } // namespace fallout