Hidden Monokumas/Danganronpa 2

Hidden Monokumas (隠れモノクマを, kakure Monokuma) are a collectible item featured in Danganronpa 2: Goodbye Despair. They are spread throughout Jabberwock Island in every chapter and appear in the overworld as a Monokuma sprite. Collecting half, then all of the 25 of them will reward the player with trophies.

Guide
Note: You are able to see what ones you're missing by looking on the Monokuma Display in Hajime Hinata's Cabin.

Hope's Peak Academy / Chapter 6
Unlike previous chapters, this chapter is linear, in that when you leave a room you are unable to return to it. As such, be sure to obtain these Hidden Monokumas in order or you will have to repeat the chapter.

Ending
After collecting all of them, Monokuma will show up in Hajime Hinata's Cabin to congratulate him, and give him his "prize". Which is just a series of Monokuma poses in his various sprites before he leaves. Hajime, understandably, is upset.

Trivia

 * The trophy name "Be Beary, Beary Quiet..." is a reference to the classic cartoon, specifically with the character Elmer Fudd saying his iconic line: "very very quiet, I'm hunting wabbits."
 * The Hidden Monokumas found in Chapter 5 are most likely a reference to 's COMP