Periscopic Clowncrab

The Periscopic Clowncrab is a small, camouflaged lifeform that hides amongst the grass-like gorgonians of the Coral Gardens.

Appearance

The periscopic clowncrab possesses a smooth, hard-shelled body with a white underbelly. The top of its body is covered in orange polygons that create veins of white.

• Reproductive Organ: In the upper middle of its body lies a smooth, orange, stalk-like reproductive organ.
• Eyestalks: Positioned at the far top front are two smooth, orange eyestalks with a small red-orange gradient. Each stalk features a large, ovular black iris facing forward.
• Mandibles: Two crab-claw-like vertical mandibles are located at the front of the body, orange at the top and white at the bottom.
• Limbs:
  • Front Limbs (Arms): Below the mandibles are a pair of legs with two joints (one downward, one upward), creating a triangular dent. These function more like arms, featuring an orange stripe on top, an orange ring before the second joint, and white elsewhere. They are tipped with a thick, singular yellow claw.
  • Back Limbs: Stretching backwards behind the arms, these limbs are fully white, vertically flat, and also tipped with a yellow claw.

Bioluminescence and Variants

At night, the tips of the clowncrab's eyestalks glow cyan, mimicking the glow of the anemone they hide in, though the irises remain visible.

A light-blue to purple variant can be found in the Necrolei Hills, where it camouflages itself within the biome's lavender anemones.

Behavior

Periscopic Clowncrabs wander the seafloor in the Coral Gardens region, usually lingering in dense patches of anemones that match their body color. They can be found alone or in small groups. These creatures are passive and curious, often staring at the player if approached.

Databank Entry

Periscopic Clowncrab

Ostrakonskelos periskopion, the hard-legged periscope. A social crab that shelters among stinging anemones.

1. Reduced body The clowncrab's single-segment body is an illusion. The multiple segments of other Protean arthropods are still present, nested inside. When the clowncrab molts, it sheds its internal shells through its digestive tract.

2. Regenerative eyestalk Enormous eyestalks mimic the surrounding raions. If bitten off by a predator, each stalk is packed with unspecialized cells that quickly regenerate missing eyes. If the stalks grow too long, the clowncrab will trim them to avoid drawing attention.

3. Raion tender The clowncrab provides a valuable service to sessile raions by ranging out to forage, returning nutrients in its molt and waste. It also grooms the raions to clean parasites and infections.

4. Fecund stalk The third stalk behind the eyes is a reproductive organ. The same unspecialized cells used to heal the eyestalks become eggs or sperm. Sperm is released into the seawater, while eggs are deposited among raions.

Assessment: sign of a healthy raion field.

Researcher Remarks

Remark A. Centipede! I think the PDA got this thing's anatomy and reproduction completely wrong. I swear I've seen centipedes — a bunch of clowncrabs linked up in a train. I think they grow as a single, segmented organism and then each segment splits off into its own crab. And then maybe they hook up again later? It wouldn't be the weirdest thing we've seen.

— K. "Wander" Wangmo

Gallery

In Game

Bioluminescence at night.

Closeup of the Shallows variant.

Periscopic Clowncrab camouflaging with grass.

A Periscopic Clowncrab cleaning its eye stalk.

A small group of Periscopic Clowncrabs.

Front view of the Periscopic Clowncrab variant found in the Necrolei Hills.

Necrolei Hills variant side view.

Trivia

• The Periscopic Clowncrab was first revealed in the Subnautica Discord server in an image posted by lead developer Anthony Gallegos on March 19, 2026.
• There is a distinct variation of the Periscopic Clowncrab within the Necrolei Hills.