Mystic Compass can be a Phantasmal Terrain which changes type each turn. Want to put together a deck with lots of "walking" creatures? Here's your chance. Your opponent will have whatever kind of land you need them to have!

Mystic Compass offers some limited "Land Destruction" capabilities. You can turn a Fallen Empires storage land into a basic land, stripping it of its counters. Or you could simply turn a multi-land into a something its owner can't use. Or you can turn their only mountain or island into something else, removing the threat of Lightning Bolts or counter spells.

The Compass can also save your own land by turning a non-basic land you own into a basic land until the end of the turn. It's a way to protect at least one land from the effects of Blood Moon, Primal Order, etc. It can also work against Conversion and Karma. It's fun for the whole family!