When Invasion of Grimskalle enters the battlefield, search your library for a snow land card, put it into the battlefield tapped, then shuffle.

Deathtouch, skulk

Whenever Naerth, Returned Rapscallion deals combat damage to a player, it fights target creature up to one target creature you don't control.

Naerth has hexproof as long as you control 3 or more snow nonland permanents.