Bitter Snows Cadaver-Finder

{w}{b}: Put an ash counter on target land.
Whenever a land with two or more ash counters on it is tapped for mana and the
mana it produced is spent to cast a creature spell, when that creature enters, it becomes
a Zombie in addition to its other types.
{t}: Bitter Snows Cadaver-Finder gets +1/+0
until end of turn and fights target Zombie.