I was trying to beat the game with as few shots as possible but on level 3 If you throw an enemy into another enemy while on the table you are sent flying up. It does nothing but end your run but I thought is was pretty funny.

I did that too, it's probably because their hitbox moves you up while you trow them because it's still active. Yes they have a bubble hitbox when you aren't invisible, that's why they move away if you get too close