Poopyface
Poopyface is one of Matthew's OCs who exists in Matthew's OC AU and presumably their main OC universe as well. He is a member of ShadowClan, the most evil Clan.
History
As fictional characters
At some point, Matthew came up with their Warrior Cats OCs Pianolove and Gloryclaw, presumably developing the characters and ideas further.[1] In the aftermath of the Crazy Noisy Showdown, Matthew made a DeviantArt account under the username Xx-warriercatz-xX, and one of their drawings featured Poopyface.[2]
In Matthew's OC AU
He killed Pianolove,[2] before he was revived with fire powers.[3]