Havengul Dredge-Mass

Emerge {5}{u}{u}{u} (You may cast this spell by sacrificing a creature and paying the emerge cost
reduced by that creature's mana value.)
When you cast Havengul Dredge-Mass, gain
control of all blue creatures without flying your opponents control for as long as Havengul
Dredge-Mass remains on the battlefield. For as
long as you control those creatures, they are
Eldrazi in addition to their other types.