Actually, it was a butterfly kit. My cousin sent it to me. (Thanks, Suzie!)
It came with painted lady caterpillars in this little jar. Their food is the yellowish stuff in there with them. They just stay in the jar and eat and grow until they pupate. The kit also came with a butterfly cage to put the chrysalids in.
I re-gifted the kit to one of the teachers at school who hasn't had a chance to have caterpillars growing in her classroom yet this year. Her kids were really excited.
By the way, the Butterfly Kit came from here, if anyone wants to know.