Slaking

You may sacrifice a creature named Vigoroth
rather than pay this spells mana cost.
Protection from Spirits.
Whenever Slaking becomes tapped, it doesn't
untap during your next untap step.
Whenever a creature is put into your graveyard
from the battlefield, Slaking gets +2/+2 until
end of turn.
You may exert Slaking as it attacks or blocks.
If you do, it gets +X/+0 and gains trample until
end of turn, where X is it's power.