-const int MONSTER_RESPAWN_DEATHPOINT = 16; // re-spawn where we died
-const int MONSTER_TYPE_FLY = 32;
-const int MONSTER_TYPE_SWIM = 64;
-const int MONSTER_SIZE_BROKEN = 128; // TODO: remove when bad models are replaced
-const int MON_FLAG_SUPERMONSTER = 256; // incredibly powerful monster
-const int MON_FLAG_RANGED = 512; // monster shoots projectiles
-const int MON_FLAG_MELEE = 1024;
-const int MON_FLAG_CRUSH = 2048; // monster can be stomped in special modes
-const int MON_FLAG_RIDE = 4096; // monster can be ridden in special modes
-const int MONSTER_SIZE_QUAKE = 8192;
+const int MONSTER_RESPAWN_DEATHPOINT = BIT(4); // re-spawn where we died
+const int MONSTER_TYPE_FLY = BIT(5);
+const int MONSTER_TYPE_SWIM = BIT(6);
+const int MONSTER_SIZE_BROKEN = BIT(7); // TODO: remove when bad models are replaced
+const int MON_FLAG_SUPERMONSTER = BIT(8); // incredibly powerful monster
+const int MON_FLAG_RANGED = BIT(9); // monster shoots projectiles
+const int MON_FLAG_MELEE = BIT(10);
+const int MON_FLAG_CRUSH = BIT(11); // monster can be stomped in special modes
+const int MON_FLAG_RIDE = BIT(12); // monster can be ridden in special modes
+const int MONSTER_SIZE_QUAKE = BIT(13);
+const int MONSTER_TYPE_PASSIVE = BIT(14); // doesn't target or chase enemies
+const int MONSTER_TYPE_UNDEAD = BIT(15); // monster is by most definitions a zombie (doesn't fully die unless gibbed)
+const int MON_FLAG_HIDDEN = BIT(16);