A sea whelk is a type of sea snail that is purple in color with light tangerine shells that are the shape of a cone with orange spikes on them. They also have no eyes and a big gaping mouth that can spit out lavender slime bubbles.
They resemble a regular sea snail without the stems leading up to the eyes and the eyes themselves. While the bodies are purple, their shells feature a light tangerine color with a circular series of spikes around each curve on the cone shell.
Throughout the episode, these snails are depicted as giants, but they can actually fit in the palm of a fish's hand.
Sea whelks have a disease that aggravates the whelks, causing a rampage while being huge in size.
Role in episode
Bikini Bottom sustains devastation due to giant whelks. It is later revealed that germs caused the whelks to be aggravated.