Bought a six-pack of this plant at the local nursery but cannot for the life of me remember what the guy at the store told me about them. I think he mentioned they can grow to be quite large which was why I bought them. I've been perusing the Internet but cannot find any decent photo identifications. Can anyone help? I made succulent pot arrangements for friends as Christmas gifts and I'm trying to make labels to instruct them on how to care but I don't know what these are called!

Thanks!