Firegeist

Hide By Firelight. In an area lit only by nonmagical flame, a Firegeist gains a +2 bonus on Stealth checks. This becomes +4 when hiding within the fire.

Illumination. The firegeist sheds dim light in a 30-foot radius.

Magical Light Sensitivity. While in magical light, the firegeist has disadvantage on attack rolls and ability checks.

Water Susceptibility. For every 5 feet the firegeist moves in water, or for every gallon of water splashed on it, it takes 3 cold damage.

Multiattack. The firegeist makes two slam attacks.

Slam. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 7 (1d6 + 4) bludgeoning damage.

Combustion Touch (Recharge 5-6). The firegeist may ignite a target when making a slam attack. The target must immediately succeed at a DC 13 Dexterity saving throw or catch fire, taking an additional 5 (1d10) fire damage at the beginning of its next turn. Until someone takes an action to douse the fire, the creature takes 5 (1d10) fire damage at the start of each of its turns.