When crawler and its variants uses its "hop on the ceiling" animations to restealth and teleport, if you watch closely, you can with some practise determine direction they teleported to. Combined with the fact that they always teleport to a wall (or pillar), on a tile no in player sight, it makes finding them quite easy.
Not sure if this is intended to reward observant palyers or just misaligned timing on the animation/teleportation.
