Selmun, Erratic Mastermind

Flash, Flying, Split Second.
When you cast Selmund, you may counter target
spell or ability that isn't a mana ability. If you do,
flip a coin until you lose a flip. Copy that spell or
ability for each flip you won.
You thought you knew my plans. You thought
you had the perfect answer. You thought you were
about to win this fight.
You thought wrong.