The Fey Pool

The pool looks safe. Soft light falls on wet stone, the ferns never dry out, and two sisters laugh like the water is already on your side. Lira Splash-Song is the warm one. She waves travellers closer, offers rest, and makes the bank feel like the only sensible place to drop a pack. Nyssa Stillwater watches from the deeper end. When she sings, the path back into the trees goes quiet and every step points toward her.

This is a resting trap, not a straight fight. If the party pays the sisters with time and trust, they may leave wet but whole.

Lira opens with charm and small requests: sit, drink, stay. She would rather keep a guest than kill one. If someone breaks the spell early, she still has barkskin and a shillelagh, and she fights with her club.

Nyssa waits until the party has settled, then sings. She stays over the deep water and lets the song do the work. Once the music stops, she closes with her claws.

Fey Charm targets one humanoid or beast that Lira can see within 30 feet. On a failed DC 14 Wisdom save, the target treats her as a trusted friend and takes her requests in the best light it can. It gets a new save each time Lira or her allies harm it, so Nyssa should leave Lira's guest alone and claw someone else. Lira can hold one humanoid and up to three beasts at a time. Her Innate Spellcasting adds entangle and goodberry, which suits a host offering food by the water. Magic Resistance gives her advantage on saves against spells. Tree Stride lets her step into one Large or bigger living tree and out of another within 60 feet, so she can leave a fight that turns against her.

Luring Song reaches every humanoid and giant within 300 feet that can hear it. On a failed DC 11 Wisdom save, the target is charmed and incapacitated, and it must move toward Nyssa by the most direct route without avoiding opportunity attacks. It can repeat the save at the end of each of its turns, before it moves into damaging terrain, and whenever it takes damage from anyone other than Nyssa. Nyssa has to spend a bonus action on each of her turns to keep singing, and the song ends if she's incapacitated.

Nyssa flies at 40 feet and walks at only 20, so she's safest in the air over the deep end while the charmed wade toward her. Anyone Lira has charmed will argue for staying. A party that wants to leave has to get past a friend's advice and a song at the same time.