Merm/Normal

Merms are aggresive mobs, which usually spawn in Marsh biomes. They live in a Rundown House. Similar to pigs, when they are attacked or haunted, they will attack the target in groups. They will drop living Fish and Frog Legs once they are dead.

Merms will attack players who get too close.

Appearance
They use the similar hunchback model like the Walruses and the Pigs. They have gills on the side of their heads and down their neck. They have eyes and an open mouth and numerous warts and bumps running across their body.

Spawning
They spawn from Rundown Houses, which randomly appear in Marsh Biomes. They spawn slowly when it's day and spawn rapidly when it's dusk. Therefore, it is recommend not to visit marsh with Rundown House at dusk, since a lot of merms will spawn and chase after the player. Also, they have high running speed and they act in groups. If you attack one of them (and manage to hit them) near a Rundown House about 3-4 Merms will spawn and immediately come to attack you. They will also aggro you if you go too close to their houses.

Strategy
They have the same Kiting AI like the other hunchback mobs, so the same strategy with pigs is recommended with Merms.

They take two blasts from the Ice Staff to be frozen.

You may also want to visit the Merms, as you may spot Tentacle Spike, Tentacle Spots and even Silk left behind after Merms have finished off Tentacle and Spiders in the marsh biome.

Trivia

 * "Merms" is actually short for "Mermen".
 * Merms are based off of "The Deep Ones" from Lovecraft.
 * Kevin answered the question "Why Merms drop fish?" in the ShannonZKiller's Pre-relase twitch. The answer was "They are made of fish."
 * A good way to get tentacle spikes/tentacle spots is to lure merms over to tentacles and they will slowly kill it.