This design is of Caboose (Michael James Caboose), a well-received and classic character of Red vs. Blue. He is stupid, silly, and very detached from reality, going so far as to drink gasoline and load his rifle with crayons. Caboose is a member of blue team, and despite his meager intelligence, is very strong, being able to throw a jeep as well as withstanding gravity increased 10 times. He has a pet that is an assault rifle/robot (Formerly a Mantis) named Freckles. Caboose held the rank of Captian in the New Republic. The character was loved by audiences because of his how funny he was. This design is of him in season 13, where he looks slightly different.

Caboose Wiki: http://rvb.wikia.com/wiki/Michael_J._Caboose