Void Worm

Void Worms are gigantic lengthy creatures that reside deep within the Void Sea, underneath the Depths of Rain World. These are the only sign of organic semi sentient creatures that are encountered in the region. Despite their sheer size and the absence of fins or any other appendages to aid in movement, they are able to move remarkably fast.

Appearance
Voids worms have silvery bodies that stretch to an incomprehensible length. Their heads are disproportionately small compared to the rest of their body, with their golden eyes and antennae-like limbs with hooks on the ends. They can be encountered in the Ascension endings for all s. Although the player only encounters one Void Worm that actively interacts with it, there are many others that can be seen and swimming in the background. The slugcat is forcefully moved in the same direction as a Void Worm when its body passes directly overhead, accompanied by a loud rumbling sound.

Encounter
In the Depths, after Slugcat jumps into the void fluid, and travels down a few screens, many void worms can be seen. Some void worms nearby can indirectly interact with Slugcat by propelling them in the direction they're heading, either beneficially or by stifling their movement. Swimming below the void worm swarm causes a Void Worm to appear with a unique rumbling sound. After a few moments of inspection and examination, if the creature is deemed worthy enough, it "hooks" Slugcat with a string, and then pulls the Slugcat upwards, then back to the depths of the Void Sea, travelling at a speed so quick it causes Slugcat to appear distorted. After a while, the void worm ceases movement and releases slugcat before heading upwards again. Upon being released, Slugcat is left in a pitch-black abyss with only a white light and music to follow to the ending of the game.

Trivia

 * In versions of the game earlier than 1.5 it was possible to be killed via fall damage from an invisible Void Worm in the room before the void sea.