Mirror-Pool Wurm

When Mirror-Pool Wurm enters the battlefield,
return target instant or sorcery card from your graveyard to your hand.
When Mirror-Pool Wurm leaves the battlefield,
put a token copy of it onto the battlefield.
"Deep in the heart of The Lorgund forest, forgotten to
some. Whispered as tales to others. Lies a treasure,
worth more than any precious gem"
Archmage Darrius