Herald of Leshrac
{6}{B}
Creature -- Avatar
2/4
Flying
Cumulative upkeep--Gain control of a land you don't control. (At the beginning of your upkeep, put an age counter on ~this~, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
~this~ gets +1/+1 for each land you control but don't own.
When ~this~ leaves the battlefield, each player gains control of each land they own that you control.