Darkdepth Schemer

When Darkdepth Schemer enters the battlefield,
you may return target creature an opponent
controls to its owner's hand. You get drowning counters equal to its converted mana cost. (At the beginning of your upkeep, put the top card of your
library into your graveyard for each drowning counter
you have.)
"The surface dwellers frolic and squabble in a world
that is not their own. When the tide rises, their pathetic empires will crumble."