Hu, pod, that's an interesting one...
Has anyone tried running Pod in shops? It is an artifact and they can have creatures going from 2-8 mana without missing a slot which isn't bad, but it does cost a lot of life and they're already paying enough to tomb an such.
It's come up before. The loss of life is relevant, and it is affected by all the prison pieces. Metalworker typically does a better job of cheating things into play than Pod.