Mexalla, Venneglade Assassin

First strike, trample, haste
Mexalla, Venneglade Assassin's power is equal to the number of land cards in all graveyards.
Mexalla, Venneglade Assassin's toughness is equal to the number of different keyword abilities among creatures you control.
{1}: Search target players library for a basic land card, and put it into that player's graveyard.
{r}{r}{r}, {t}: Destroy target land.