Atolla jellyfish
The body of "Atolla wyvillei" is a bell shape and it has several moderately long tentacles along the bell. The bell is around 20–174 mm in diameter. It also has a single long tentacle called a hypertrophied tentacle. This hypertrophied tentacle has several purposes, including aid in predation and aid in reproduction. These jellyfish do not have a digestive system, a respiratory system, a circulatory system or a central nervous system. Not having a central nervous system means that it lacks a brain.
List of SpongeBob SquarePants characters
The Jellyfish (vocal effects by Tom Kenny) are wild animals who reside in Jellyfish Fields, a meadow in Bikini Bottom, and have a strong affinity for music. Within the series, jellyfish behave like sentient insects, squirt jelly, buzz and swarm like bees, and can sting their enemies with electric shocks that leave painful welts.