Manashifter Borlon

Flash
Convoke (Your creatures can help cast this spell.
Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
When Manashifter Borlon enters the battlefield,
you may gain control of target creature that
entered the battlefield this turn. If you don't,
each opponent puts the top card of their library
into their graveyard.