Counterlash

Look at target opponent's sideboard. You may cast a card from that sideboard without paying its mana cost.

Exile Command the Chaff.

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost.

Counter target spell.

You may exile a blue card from your hand rather than pay this spell's mana cost.

Change the target of target spell with a single target.

Counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard. You may play it without paying its mana cost for as long as it remains exiled. (If it has X in its mana cost, X is 0.)

Counter target spell. You may cast a creature, instant, sorcery, or planeswalker spell from your graveyard with mana value less than or equal to that spell's mana value without paying its mana cost.

Draw three cards. Then target opponent faces a villainous choice — They discard three cards, or you may cast a spell from your hand without paying its mana cost.