it's their stomachs
just a big ball with legs something like that
A circle.
Circle, semi-circle, cresent
Moon jellies are translucent, appearing almost colorless with a delicate shimmer that makes them look like they are glowing. They have a saucer-like shape with short tentacles hanging down in a fringe along the edge of their bell. These jellyfish have a gentle pulsing movement as they drift through the water.
Jellyfish come in many different sizes. Many are small and can fit in the palm of your hand. Others are much larger than humans.
the moon isn't a perfect sphere its kinda like a oval in a way The shape of the moon is an oblate spheroid, just like earth
The moon jellyfish has one stomach.
The jellyfish is translucent, usually about 25-40 cm (10-16 in) in diameter, and can be recognized by its four horseshoe-shaped gonads, easily seen through the top of the bell.
moon jellyfish
The scientific name for moon jellyfish is Aurelia aurita
Whales, turtles, and larger types of fish all eat the moon jellyfish. The moon jellyfish is thought to have existed for millions of years.
The moon can look like a semicircle, a fingernail crescent, a gibbous (egg shaped moon) and of course it can look like a complete circle.