Kiora Bests the Sea God
Oracle Text
I — Create an 8/8 blue Kraken creature token with hexproof.
II — Tap all nonland permanents target opponent controls. They don't untap during their controller's next untap step.
III — Gain control of target permanent an opponent controls. Untap it.
If the opponent is down to 16 or less it is very hard to avoid this from killing, and otherwise it's still damn good value.
Would be sad if this gets too popular as the one to land this first in a mirror has a huge advantage by getting to steal theirs.
Play Kiora Bests the Sea God
Get an 8/8
Opponent then plays Kiora Bests the Sea God
Tap their stuff
They tap your stuff
Steal their Kiora Bests the Sea God
Steal something else
I think it's highly unlikely this will ever happen.
I'd double check the rules on hexproof
I believe he was referring to the fact that you can steal their Saga, not the Kraken.