Can you hard cast Sprite Call as an attacker, and how does it work in FFA format when cast as a 3rd party?

Ruling: You cannot hard cast Sprite Call as an attacker to the battlefield you're attacking because you don't control it. However, you can play it during that showdown to your own base/battlefield that you do control.

Nuances:

• In FFA format as a 3rd party, you cannot play it to help an ally in a 2v2 scenario because you cannot have more than 2 players' units present at a battlefield at the same time.