Rainbow Jellyfish are passive Mobs found in the Shipwrecked DLC. Similar to regular Jellyfish, they float around in the Ocean, sometimes in groups. They will not attack the player or flee if they are approached. They will not shock the player on contact as regular Jellyfish do. Once killed, their carcass will float in the water until picked up.
Rainbow Jellyfish can also be caught alive using a Net or a Trawl Net. As inventory items, they can be murdered by right-clicking them to produce Dead Rainbow Jellyfish. A Rainbow Jellyfish placed on the ground will immediately turn into a Dead Rainbow Jellyfish. They will have a short animation where they twitch twice before settling.
Rainbow Jellyfish can be cooked to make Cooked Rainbow Jellyfish, while Dead Rainbow Jellyfish can be dried on a Drying Rack to obtain Dried Jellyfish. Rainbow Jellyfish cannot be used in the Crock Pot.
Rainbow Jellyfish take 2 blasts from the Ice Staff to be frozen and 1 Sleep Dart to be put to sleep. They are considered innocent creatures, and killing one adds 1 point to the player's naughtiness level, which can cause Krampus to appear.[Verification Needed]
During Full Moon nights, sometimes Rainbow Jellyfish migrations can take place. They will spawn in large groups and travel together towards the Volcano. After the night ends, they will slowly disappear again.
- Rainbow Jellyfish were added to the Shipwrecked DLC more than a year after its official completion in an unnamed beta update.