I feel like it should have an ability like "When Zergling enters the battlefield, put a token into play that is a copy of it" or something along those lines to capture the flavor of two zerglings from one larva. Also the Beast creature type just seems wrong.
i'd think it should be a spell card that has "set two zergling tokens on the battlefield with haste" kind of like the goblin card of the same trick [but without haste].
Still, I don't think I would run more than four of these guys even if I could. Maybe just leave it as a zerg form of Raging Goblin?
What would you have instead of Beast?
kind of like the goblin card of the same trick [but without haste].