Encounter of the Week: Sea Trolls in the Net

High tide is coming in in this week’s encounter: Sea Trolls in the Net, a tongue-in-cheek combat encounter about a troll troubling fishermen and getting tangled up in their net. This encounter works best when it can add flavor to a grim, seaside locale as a random encounter the adventurers stumble across while exploring. While exploring a blighted shoreline on some forsaken coast, the adventurers find a sea troll feasting upon fishing nets full of freshly caught fish while their fishermen flee from the shore.  

Combat Encounter: Sea Trolls in the Net

This combat encounter is suited for characters of 5th level, but it can be scaled up to challenge a higher-level party.

This encounter is intended to be set on a dark and stormy coast, but it can also be set on a sandbar at sea, on a fishing vessel, or any other location with easy access to a large body of water. This encounter also introduces the skrag, otherwise known as a sea troll. A sea troll’s statistics are identical to that of a troll, except it has a swimming speed of 30 feet, and can hold its breath for up to 10 minutes. It also has the following attack, and it can make this attack in place of a claw attack when using its Multiattack action:

Harpoon. Melee or Ranged Weapon Attack: +7 to hit, reach 5 ft. or range 30/120 ft., one target. Hit: 11 (2d6 + 4) piercing damage. The skrag has 5 harpoons.

Any type of troll, such as a venom troll or dire troll from Mordenkainen’s Tome of Foes can be made into a sea troll. For example, a dire skrag has the statistics of a dire troll, but also has a swimming speed of 30 feet, and can hold its breath for up to 10 minutes. Its harpoon attack uses the same bonus to hit as its Claw attack, and deals 13 (2d6 + 6) piercing damage, because of its Strength score of 22 (+6).

This encounter uses the Loathsome Limbs variant trait, presented in the Monster Manual.

At Higher Levels: If the characters are at least 11th level, replace the skrag with three venom skrags. They all have a magical key (see “Magical Key,” below). If the characters are at least 17th level, replace the skrag with three rot skrags and one dire skrag.

Encounter Summary

The characters hear the screams of fleeing fishermen while traveling across the coast, and soon find themselves nearly face-to-face with a sea troll, as it gorges itself on the fishermen’s catch. The troll is spoiling for a fight, and as soon as the troll sees new targets—the characters—it stops feasting and begins hurling vicious insults at them, in an attempt to provoke them to attack it. The encounter ends when the troll is defeated or when the characters flee.

Encounter Start

While the characters are traveling along a dark and stormy seashore, read or paraphrase the following:

The peaceful sound of rain pelting the surface of the dark sea is suddenly disturbed by screams. You see a half dozen people carrying nets, fishing poles, and harpoons fleeing from the shore. One of them briefly stops to catch her breath and catches your eye. “Sea troll,” she snarls. “The damn skrag rose out of the sea and got itself tangled in the net. We’re from the next village over, and those fish we caught were gonna feed our families for the next week. But I’d rather forage for berries than let myself get torn apart. If you need to go this way, give the thing a wide berth!”

The woman bids you a wordless goodbye and runs after her companions.

If the characters continue onward in the direction the fishermen fled from, they see the sea troll tangled up in a fishing net, greedily feasting upon dozens of flopping fish. If the characters don’t approach stealthily, the troll notices them as soon as they notice it. If the characters do approach stealthily, they must make a successful DC 12 group Dexterity (Stealth) check to avoid alerting the troll. They can make this check even without cover, since the troll is looking at the ground to find the next fish it wants to devour.

A character that makes a successful DC 15 Wisdom (Perception) check notices that the troll’s limbs are covered with a dozen fat leeches. These leeches are dormant, but awaken and detach as soon as the limb they are attached to is severed (see “Loathsome Limbs,” in the Monster Manual). Detached leeches crawl hungrily towards the characters. Each of the troll’s arms and legs have three leeches attached to it. These leeches use stirge statistics, with the following change: it doesn’t have a flying speed, and instead has a swimming speed of 40 feet.

Once the sea   troll notices the adventurers, it lets the fish it’s holding drop to the ground with a soggy slap. It grabs a driftwood board from the shore and loudly clacks its long claws against the board and bellowing, attempting to drive the adventurers away. If they don’t retreat, roll initiative! On the troll’s first turn in combat, it touches a glimmering silver key tied around its neck with one hand, while continuing to clack its other hand on the board. It then roars a disturbing insult at one of the characters, and casts vicious mockery using the magical key (see below). You should tailor this insult to fit your party, but you can use a generic insult as well. One insult the troll could shout, translated from Giant, is, “You look just as soft and shreddable as those fishermen. Will you bleed and squish just like a fish?”  

Magical Key

This troll possesses a magical key, that allows it to cast vicious mockery with a spell save DC of 13 as a bonus action. It likes to do so by spewing insults while making a raucous din by clacking its claws against driftwood boards, or smashing those boards against rocks. Though the troll only speaks Giant, its words still sting, even if the target of its mockery can’t understand it.

The troll fights like a berserker, wading into combat with no care for its own well-being—until the characters reveal that they possess the ability to hurt it with acid or fire. If the troll knows that they can halt its regeneration, it flees from combat once it is reduced to 20 hit points.


If the sea troll flees from the nets, it lurks for 1d6 days before it attacks this fishing spot again. The fishermen know this, and thank the characters for scaring the troll off, but morosely agree that it will return soon, and likely in greater numbers. If the adventurers kill the troll, the fishermen sing their praises and throw them a feast back in town. Before the feast, the fisherwoman who met the characters before visits them and says, “While I was cleaning one of the fish, I found a strange-looking ring in its guts. It’s pretty, and probably worth something. We don’t have a lot to give, but I figure you deserve this.”

The ring is a ring of mind shielding.

If the characters kill the troll, they can plunder the magic key from its neck. However, this key comes with a curse. It requires attunement to use, and a creature that is attuned to it drifts slowly in alignment towards chaotic evil, moving one step along either the law-chaos or good-evil axis every 1d10 days. A creature afflicted by this curse also gains the following flaw: “I love causing other people’s suffering, and I can’t talk with someone without insulting them and trying to get a rise out of them.”

A creature attuned to this item can’t remove it unless it is targeted by remove curse or similar magic.  

Did you like this encounter? If you want to read more adventures, take a look at the other encounters in the Encounter of the Week series! If you're looking for full adventures instead of short encounters, you can pick up the adventures I've written on the DMs Guild, such as The Temple of Shattered Minds, a suspenseful eldritch mystery with a mind flayer villain (for 3rd level characters). My most recent adventures are included in the Gold Best Seller Tactical Maps: Adventure Atlas, a collection of 88 unique encounters created by the Guild Adepts, which can be paired with the beautiful tactical poster maps in Tactical Maps Reincarnated, recently published by Wizards of the Coast.

James Haeck is the lead writer for D&D Beyond, the co-author of  Waterdeep: Dragon Heist and the Critical Role Tal'Dorei Campaign Setting, the DM of  Worlds Apartand a freelance writer for Wizards of the Coast, the D&D Adventurers League, and Kobold Press. He lives in Seattle, Washington with his partner Hannah and their feline adventurers Mei and Marzipan. You can usually find him wasting time on Twitter at @jamesjhaeck.


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