Merm/Normal

Don't Starve=

Shipwrecked=

Don't Starve Together=

"What foul sea did that crawl out of?"

- Woodie

Merms are semi-aggressive Mobs found in Marshes that live in Rundown Houses. They are covered in dark green scales, and they have bulging eyes, gaping mouths, and gills on the sides of their heads.

They take two blasts from the Ice Staff to be frozen and just one Sleep Dart to be put to sleep. Merms drop raw Fish and Frog Legs when killed, and these remains can often be found in marshes after Merms battle with Tentacles.

Also, Merms eat fruits (like Berries), Vegetables, Mandrakes, and even Crock Pot Recipes. However, they will not eat Seeds or Honey.

Shipwrecked
Merms also appear in Don't Starve: Shipwrecked DLC, with minor differences. In the DLC, they will drop Tropical Fish instead of Fish and Frog Legs. Merms in Shipwrecked live in and spawn from Merm Huts, instead of Rundown Houses. The DLC also introduces a passive variant of Merms, called Fishermerm.

Behavior
Merms spawn from Rundown Houses, which randomly appear in Marsh Biomes. A Rundown House can house up to 4 Merms, and it respawns a Merm in 4 days after it's killed. During the Day, only 1 Merm per Rundown House is normally outside (unless it gets into combat, then all other Merms come out), and when dusk comes, all Merms go outside, much like Spiders. Merms will only attack if the player or any other mob gets too close to their house. Similar to Pigs, when they are provoked, they will attack in groups and will kite.

Hunting
Merms can be kited, very similarly to Pigs. Thanks to the hostile nature of the marsh biome, Merms are often discovered in pitched battle with Tentacles, Spiders, or both. For this reason, they make for an excellent source of Tentacle Spikes, Tentacle Spots, Monster Meat, Fish, Frog Legs, Spider Glands and Silk: Simply wait for the Merms to finish fighting, then clean up what they leave.

It is not recommended to fight several Merms at once, as they run faster than the player and will kite, like Pigs. Once the player runs some distance apart from a Merm, it will stop being aggressive and will walk back to its house.

To start a battle between Merms and Tentacles, fruits or vegetables can be used as bait for a Merm. Put at least one or two pieces on the ground near a Tentacle or more, near enough to a Rundown House. When a Merm finds the food, it will approach and eat them one by one. There is a good chance the Tentacle(s) will attack the Merm, and then more Merms will come out to fight. A similar way can be done by making it chase the player and pass by a tentacle, which, if timed correctly, will hit it.

Below is the number of hits it takes with each weapon to kill Merms when playing with characters with a default damage modifier. The Weather Pain is not included due to the random nature of its projectile.

Trivia

 * Merms were added in the A Little Rain Must Fall update.
 * "Merm" is an abbreviation for "Merman", a man-sized creature with the tail of a fish.
 * Merms are almost certainly based on The Deep Ones, a race of fish people from the horror fiction of American author H. P. Lovecraft, who live in Innsmouth, a run-down town similar to Don't Starve's Merm towns.
 * Kevin (Klei's lead developer) answered the question "Why do Merms drop Fish?" in the ShannonZKiller's pre-release Twitch video. The answer was "They are made of fish".
 * Merms are not created by Maxwell like other monsters, judging by his quote, "They were here when I got here."
 * Pig Heads, as of The End is Nigh update, spawn in Merm villages, and along Roads passing through Marshes. This suggests some kind of hostility between the two tribes of animals. Similarly, Merm Heads spawn inside some Pig villages.
 * Merms are instantly hostile (unless fighting something else) when spawned via the Console because they have no house to placate them.
 * Merms seem to have normal walking speed, but during dusk they are faster. They are also faster than Pigs; however, they can be easily outrun any time if they are aggressive because they briefly stop running to attack.

Bugs

 * Merms may continue to attack the location of a tentacle after the tentacle has been killed.

Gallery
Merm Merm