Esna, Byron's Blade

Ninjutsu {1}{u}{b}
When Esna, Byron's Blade deals combat damage
to a player, that player reveals their hand.
Choose target instant or sorcery their hand.
You may cast that spell without paying it's
mana cost until end of turn.
{u}{u}{b}{b}: Return Esna, Byron's Blade to it's
owner's hand.