Pufferfish

Within the fandom, Pufferfish is known for having one of the best character arcs on the show, with a tear-jerking redemption arc. Outside of the fandom, he has become notorious for a certain incident that culminated in the burning down of the White House.

Pufferfish was an antagonist, frequently doing antagonist-y things, such as mass murder and loitering. However, he slowly revealed his tragic backstory -- he was unwanted as a child, and his traumas led to him becoming the way he was. His friendship with the protagonists caused him to change his spiky ways. He saved their lives many times over, and he quickly became a fan favourite. The hoardes of Hillbilly Handfishin' fans across social media rejoiced when he gave up his evil ways for good at the Battle of the Mariana Trench and become a full protagonist. He is round.