Really Happy Mouse is a antagonist in Abandoned: Discovery Island 3.0.
Really Happy Mouse's appearance is that of Suicide Mouse, except he has human like teeth. Within darker colour scheme. One of his eye-holes are larger/wider.
He is like Suicide Mouse, but with a smile, is withered and broken almost everywhere in himself.
Really Happy Mouse will start in Character Prep 3 with Willy, then he will go to the Character Prep 1, then to the Staff Area , then to the meat freezer, then to the Lounge, then finally to the office.
- Really Happy Mouse is named after the game "Really Happy Mouse". (Obviously by now)
- He is a happier verison of Happy Mouse himself.
- He can be seen broken/withered in his new promo. While his old promo is not broken/withered.