Keyword Ability. A minion with Burrowing can be summoned to underground locations and survive underground. By using one step, a minion with Burrowing can move between the surface and subsurface of a land site, or between adjacent underground locations. A minion with both the Burrowing and Submerge abilities can move directly from an underground location to an underwater location in an adjacent square, and vice versa, in one step. For example, Cave Trolls can be summoned underground to one of your land sites. Then, after their summoning sickness wore off, they could use their Move and Attack ability to take a step from underground to the surface of that site (and that would use up their step). If they were on the surface of a land site, they could use their step to move from the surface to underground of that site. To 'burrow' means to move from the surface to the underground of a land site. When an effect 'burrows' a card, you forcefully move that card from the surface to underground, even if it doesn't have the Burrowing ability. If an effect tries to forcefully burrow (e.g. Bury) a card that occupies at least one water site, the effect fails.