It comes in a tube.(jel like) It is used for low sugar. It is a "must have" IMO. If they are not eating it can also jumpstart their appetite. (so I've read) I give about a pea size on my finger and Penny licks it off. I think I've only used it 2-3 times. But I always keep it for emergencies.
Penny also had a playpen (baby kind) she hated it, so we took it back the next day. However, she loves her crate. That is her safe haven. Especially if we are gone and she has to stay home. She has a bed, food, and water and her favorite toys.