Hee. So I can cast it whenever I could cast a sorcery or a creature. Either way, on the stack it's an artifact creature sorcery spell. When resolving, since the game asks "Are you a creature spell?" and gets "yes", it goes onto the battlefield.

Odd things happen when you start copying this with Izzet Guildmage or Panoptic Mirror. I think it all works fine if you assume the Rules Team eventually get around to saying that copies of creature spells become creature tokens.

I presume this was more for tutoring it out; or flashing it back. But mm, rules oddness is always yummy.

Eww, flashback. Unfortunately it doesn't work anywhere near as well with Recoup / Past in Flames as people would like. You can grant it flashback, and then cast it... but when it leaves the stack and would enter the battlefield, flashback steps in and says "Nuh-uh. From the stack, the only place you can go is the exile zone."

I asked Matt Tabak if this would work, and he said "Yes, but why would you want it to?" or something to that effect.