Vacuum Snack! Trophy

You will ride a Moskito-back, at the end of each world, as well as during certain Hidden Cage sequences. While on a Moskito-back, you can suck in objects with them by holding either or to inhale an enemy. Inhale 50 enemies or objects, and the trophy will pop.

Inhaling enemies and firing them back more enemies at once than your regular fire anyways, so you will most likely unlock this trophy naturally. Note that this trophy is cumulative, so you don't need to do it all in one level.