King Critcrab

Spiciness: 5/5

This is boss fight material. While not particularly high damage, most characters are not equipped to fight underwater, and that can result in

Feeds about 3-6 players, level 5-8

Scales for: Number of Players, Player Level

Ingredients:

• The King Critcrab
• A Harpy
• X Sahuagins, where X is the size of the party.

Scale for Level: Give the Critcrab 10 additional HP for every level above 5. At level 7, add +1 to ALL Save DCs.

Preparation

The Critcrab is not just a creature-- it's the center of an ecosystem, a community of collaborators. A Harpy has made a nest on the Critcrab's back, luring in potential food for it. Underneath, Sahuagins wait to loot the remains of the Critcrab's meals.

Important things to know for this encounter:

• While Underwater:
• A creature can hold its breath for a number of minutes equal to 1 + its Constitution modifier (minimum of 30 seconds). When a creature runs out of breath or is choking, it can survive for a number of rounds equal to its Constitution modifier (minimum of 1 round). At the start of its next turn, it drops to 0 hit points and is dying, and it can't regain hit points or be stabilized until it can breathe again.
• If you're holding your breath, you can't do vocal components of spells.
• When making a melee weapon attack, a creature that doesn't have a swimming speed (either natural or granted by magic) has disadvantage on the attack roll unless the weapon is a dagger, javelin, shortsword, spear, or trident.
• A ranged weapon attack automatically misses a target beyond the weapon's normal range. Even against a target within normal range, the attack roll has disadvantage unless the weapon is a crossbow, a net, or a weapon that is thrown like a javelin (including a spear, trident, or dart).

Pre-battle setup: The party will see a strange coral reef, floating in the ocean-- this is the critcrab, using it's Shell Camouflage to be unassuming. Put a treasure chest, a skeleton, something on it's back to entice them in to check it out. Meanwhile, the Sahaugins wait under it, and the harpy flies about 700ft above it (this is important). Since it's more than 0.13 miles, it's unlikely the party would notice the Harpy or even realize that it isn't a bird, but the Harpy is patiently waiting for anything to get close to the crab.

When a creature gets within 50ft of the crab, roll initiative and a DC 16 Perception check to notice the harpy dropping down into position. Any party members who fail are Surprised.

Cooking the Harpy

Round 1: You can drop 500ft in a round, as per the falling rules, so do that! Now that you're within 200ft of the back of the crab, use your Song to lure the party into the crab's reach (and off it's back if necessary).

Round 2+: Continue to stay at 200ft up (see High Altitude Combat for why), and keep as many people as possible charmed. The Harpy's role is Crowd Control. If someone gets knocked unconscious, you can use the harpy to rush in and finish them off with their 2 melee attacks (2 melee attacks at 5ft against an unconscious person means 2 auto-crits and thus 4 failed death saves).

High Altitude Combat: Since you're 200ft high now, your 300ft radious song ability will effect only 223 ft around sea level-- that's the Pythagorean theorem at work! That's still way more than enough to hit the whole party though, and many spells won't be able to reach you at this distance. Eldritch blast, for example, only has a range of 120ft. Longbows, crossbows, & Shortbows will have disadvantage at this range (even while directly beneath you) and hand crossbows are completely unable to hit you. NEAT!

Cooking the Sahuagin

Round 1+: Sahuagins are there for extra damage-- if the Critcrab is holding someone underwater, they swim up and stab it with spears. If a creature starts to get away, they chase it down with their impressive swim speed. Also, consider swapping out one of their attacks with a Grapple if a creature is escaping-- keeping them underwater is key.

Passives: Don't forget that they have advantage on attacks against literally every creature that doesn't have full HP!

Want a little extra spice?

Make the water Murky enough to restrict vision to 5 or 10ft out. Critcrab's Electroreception will make that not effect him, and being blind will stop them from casting any spells at further than that range. Hard to cast fireball when you've reduced the range to 10ft!