Because creatures cast this turn would get to attack during an extra turn. I get it, but I feel that's past blue even with the currently discussed idea of expanding where extra combat steps go into the color.

Even during Planar Chaos blue has been the "haste, but only if it's not for attacking"-color, so that clearly makes this stinky.

I'd love a card like... Seize the Fray.

Maybe I'm missing something about this being an instant, but that feels like unnecessarily risky for confusing interactions.

I did make this card during a discussion elsewhere about the blue getting extra combats change. Wotc is intentionally leaning into aesthetic bends for hybrid now, such as blue/red getting menace. I think it's at least in the area for discussion here

You're right this shouldn't be an instant, but that's how it came to me

I love the name of your version