Mottled seasnail (lat. Aplysia) is a slug that belongs to the genus Aplysia. It is a snail with a reduced shell that inhabits the Indo-Pacific, Atlantic and Mediterranean seas. It is dark brown to reddish in color with whitish spots, and can grow up to 70 cm, which is why it is among the largest snails in our sea. It feeds on algae, and in late summer and early autumn it can often be seen along the coast, where it comes to mate and lay eggs. When it feels threatened, it releases a dark purple liquid for defensive purposes. Due to the specific structure of the nervous system (unusually large neurons), it is often the subject of neurophysiological research.