u/DazzlingChapter8212

My 8 year old is fascinated by animatronics. He has 3d printed and decorated a FNAF bear head and wants to build a body then have the head turn side to side. Can anyone guide us into an easy (ish) way to do this please? I wondered about a deer motor but I'm unsure whether it would be small enough and whether we'd manage to link it to a battery pack? He has a spare dc motor from a craft kit so perhaps there's a way to make that turn left to right instead of constantly spinning? Idiots guide needed please 🫣