Hlorses
From Blaseball Wiki
Hlorses are bipedal. Hlorses are Fast. Two horses cannot physically fit into a hlorse costume and attempt to gain entry to a blaseball game, so don't worry about it. Many league players are hlorses.
While Horses are not allowed at league games, Hlorses are. Hlorses however are subject to the Gum Curse and cannot chew Gum.