My little guy, newly 2, gets these random "obsessions" that he gets so fixated on! Some are normal (trucks and trains) and some can be pretty unusual, like currently, he's very into windshield wipers on vehicles... :P They don't get to the point where they make it so he can't do other things, but to the point where he talks about them A LOT! Wants to draw pictures of them, tells everyone about them, wakes up in the morning talking about them...
My Oldest never did this, and from I see, it's not something most other toddlers do, either. At least not to this extent.
I've seen people mention this is an autistic spectrum trait or OCD... though I've never seen anything that would make me think there is anything like going on with him. He's really social (well, with people he knows, not so much strangers) and emotionally perceptive in addition to being extremely bright. And he's been screened (his doctor screens at 18 & 24 months) and came out low risk.
Does this obsessive stuff go with the territory in gifted kids what from you've all experienced?