Its story
What it looks like
A crown of pale, finger-long coral rises from a reef shelf, its tips curled inward like the teeth of a sea urchin.
Fine strands of translucent tissue trail from the crown and stir even when the water is still.
Why it is here
An organic defense that makes vulnerable reef passages dangerous to careless swimmers.
Who made it
Unknown.
Reef divers tell of similar crowns in several island chains, but no maker has been identified.
Lore
The crown's translucent strands are sensory tissues, not ordinary coral polyps.
Reef guides warn that their pale color blends with sunlit sand, and that a cloud of fine silt often settles around a crown after it lashes.
Where it is found
Shallow reefs, submerged shelves, and coral passages in warm coastal waters.
Variants
A deep-water crown has dark, glassy branches that are harder to see in dim light.
A reef passage may contain several crowns, each a separate hazard with its own trigger and defenses.
A spent crown may be harmless for a short time after lashing, then reset as its tendrils slowly unfurl.