What the heck is wrong with my sim!?!?

My sims had a baby and when they brought her home, she...wasn't a baby. She was this weird mutant glitchy thing and it's really really freaky. She has a horse body and long creepy skin color claws and boots. WTF? How do I change this? How do I make her a normal sim. I don't want a scary crazy horse mutation. I don't even have the sims pets. Help!