[2023] Fun fact: this is what happens when you trigger a play skill on summon. I wonder if this is expected by the devs or unintended.

Hey that's me! We have indeed aligned on changing it to Play in a future patch; our system can handle creating skills at weird timings like mid-combat, but it's not intuitive and we try to avoid it as much as we can.

I mean more that we almost always change it in dev before it releases, but our system is thankfully very robust so it's not a huge deal if it ships.

For example, Avenging Vastaya used to create his ambush skill when he transformed for any reason. If you Hextech Transmogulator'd something else into him while combat was resolving, he'd put it on the stack as the very last thing to resolve. Technically functional, but unintuitive enough to change his card text to completely prevent it.

Oh, that doesn't use a skill so it's all fine and good! Giga Gromp + Transmogulator is a personal fave, I made a whole deck around it when we were in Bandlewood dev. It's actually the reason most Ambush units don't say they need to be transformed by their Ambush spell.