Roil Elemental | Magic: The Gathering
Formats Roil Elemental is Legal in
Official Oracle Text for Roil Elemental
Landfall — Whenever a land enters the battlefield under your control, you may gain control of target creature for as long as you control Roil Elemental.
Official Rulings for Roil Elemental
10/1/2009 : When a land enters the battlefield under your control, each landfall ability of the permanents you control will trigger. You can put them on the stack in any order. The last ability you put on the stack will be the first one that resolves.
10/1/2009 : If Roil Elemental leaves the battlefield, you no longer control it, so all of its control-change effects end.
10/1/2009 : If Roil Elemental ceases to be under your control before its ability resolves, you won't gain control of the targeted creature at all.
10/1/2009 : You may target a creature you already control with Roil Elemental's ability. This will usually have no visible effect, but it will overwrite any previous control-change effects. For example, if you gain control of Roil Elemental until the end of the turn (with Mark of Mutiny, perhaps), then its landfall ability triggers and you target Roil Elemental itself, you'll gain control of it indefinitely (since its control-change effect will last for as long as you control it).