Alligator

An alligator waits where dark water meets a firm bank, leaving only its eyes and nostrils exposed. It attacks the first creature that kneels, wades or turns away, then uses the water to make resistance difficult. Old animals learn the repeated paths of livestock and travelers and may remain beside one crossing for years.

Death Roll: piercing, melee 5 ft, +3 to hit, 2d6+2. The target makes a Quick save; on a failed save, it is held. In water, the held target takes 1d8 damage at the start of each turn until it or an ally uses a turn and succeeds on a Tough save to force the jaws apart.

Waterline Ambush: while only its eyes and nose are exposed, the alligator gains +2 AC against attacks from farther than 10 ft. Moving at least 15 ft from the bank prevents Death Roll from dealing its additional damage.