Neurotoxin that is probably only defensive (Probable). Acts as a voltage-gated potassium channel (Kv) inhibitor (By similarity). In vivo, induces a rapid increase in swimming speed on zebrafish larvae, as well as death which occurs between 2 and 18 hours later (PubMed:29424690). In unfertilized eggs and early post-fertilization stages, is expressed uniformly. In gastrulae, the expression becomes spatially-localized and seems to be absent from the oral and aboral poles. In planulae, the expression is clearly observed in the ectoderm in packed gland cells absent from the two body poles, and upon metamorphosis, the expression diminishes. There is two types of gland cells, one large and elongated and another small and round. This toxin is maternally deposited at both protein and RNA levels. Highly expressed in unfertilized eggs, late planulae, primary polyps, and adult females (at protein level). Not expressed in adult males (at protein level). Consistant with protein expression, transcripts are highly expressed in unfertilized eggs, blastulae, gastrulae, early and late planulae, metamorphosing planulae, and adult females. Its expression is moderate in primary polyps. Its expression is very low in juvenile polyps, and adult males. Contains 4 disulfide bonds. Belongs to the sea anemone type 5 potassium channel toxin family. Extended N-terminus.