← Back Theory about the game Subnautica. This is a slideshow I actually presented to my friends once.
Theory Overview

In the Red Grass Biome in the game Subnautica there are small predatory creatures known as Biters. They are 94% muscle, 4% connective tissue, and 2% brain. They are a minor nuisance to the player character. Near to some of the Red Grass Biomes is a cave, the Jellyshroom Biome. The cave is full of large, purple, bioluminescent mushrooms that are home to large, dangerous carnivores known as Crabsnakes.

The similar appearances and biome proximity have lead me to believe that Biters are juvenile Crabsnakes.

A Big Issue

There’s one major flaw in my theory. In game you can hatch and raise a variety of creatures. For larger creatures they hatch as a miniature versions of their adult selves, only growing to their full size if released into the wild.
Crabsnakes are one of the creatures you can hatch, and as such their young form is canonically just a smaller crabsnake.
This has been handwaved away as simply game mechanics and ignored in favour of having fun.

Section 1: Similarities

the physical similarities to the two species share

Patterning

Both Crabsnakes and Biters are pink with a lighter underbelly. As pointed out, Biter’s have more of a blue while the Crabsnake’s is white. Biters also are capable of bioluminescence, which is blue. I believe the chemical which cause the glow tint parts of the Biter’s body, which stops being produced as it ages.

Biters are more red, to blend in better with the Redgrass. Crabsnakes are more pink to match the Jellyshrooms and the pink lighting given off by the mushrooms.

As you can see, both Biters and Crabsnakes have stripes running down their back. The Biter’s have a slightly more blue hue, which I attribute to the presence of a bioluminescent chemical, like with the belly.

Movement

the physical similarities to the two species share