Mine, Foam

Unlike grenades, which explode shortly after being thrown, mines are designed to detonate once a specific trigger occurs. As an action, you can set a mine in an unoccupied space within 5 feet of you. When you set a mine, determine the circumstances under which the mine will detonate. For example, you can set the mine to detonate on a timer, when a creature enters the mine’s space, or under other specific circumstances (such as when a door opens or a vehicle activates). You can also rig the mine to detonate remotely using a remote detonator.

When detonated, a mine functions identically to the grenade it emulates.

When detonated, a foam mine fills a 10-foot-radius sphere with slippery, fire-retardant foam. Open flames in the area when the mine explodes are immediately extinguished. For the next minute, the ground in the area is difficult terrain. A creature in the affected area or one that enters the area for the first time on a turn or begins its turn in the area, makes a DC 10 Dexterity saving throw, falling prone on a failure.