You must have done something really wrong. Goniopora/flower pot coral don't have sweeper tentacles. It must have mutated due to bio hazard exposure.
No sweeper tentacles, but that's what it's doing.
Quoted from Encyclopedia of Life
eol.org)"Flowerpot corals, despite their delicate names, are generally aggressive animals (3). They are capable of developing elongated 'sweeper' polyps, like the sweeper tentacles of other corals, which can inflict severe tissue damage on a coral within their reach."



