Ya, not worms.
Acontia filaments and sweeper tentacles are two physically very different things "“ sweeper tentacles are modified tentacles of the coral polyp which are a little or much further reaching, and which usually pack a denser payload of nematocysts than other tentacles. On the other hand Acontial filaments originate from the gastric cavity and these have an even higher density of stinging cells and other digestive nasties to nuke a coral neighbor. Acontia filemants are most often seen in SPS corals and also commonly seen poking out the sides of stressed mushroom anemones, or even through the tissues of LPS corals like Scolymia and Acanthastrea.