Blue-purple to mauve bell with on top 10-50 knobs, only the peripheral region of the bell flexes, wide skirt with somewhere between 70 and 100 filaments hanging from it. Exquisite animal.
Quite common.
East Atlantic, the Red Sea and Indo-Pacific.
–
Up to 15cm.
It feeds on zooplankton.
Small fish sometimes hide between the tentacles, immune to their sting.