Hydro jelly

Hydro jellies are a type of obstacle in. They resemble a glob of translucent blue gelatinous material, and can be found in clumps of different sizes. To be destroyed, they must first be frozen and then shattered. For the most part, hydro jellies merely block the way, but some contain objects inside like treasures, castaways, Flarlic, or raw materials.

Mechanics
When most Pikmin try to attack one, its attacks cause no effect, and eventually the Pikmin gives up. In addition, most Pikmin will fail to latch on to one when thrown. Ice Pikmin that are thrown or idle nearby will however latch on, and while their attacks do not drop the obstacle's health, they do start freezing it. After it is successfully frozen, or hit with an ice blast, other Pikmin types, the player character, and Oatchi will be able to hit it and destroy it. Oatchi's rush and fire starters are able to destroy them in one hit. Some ice enemies' attacks can freeze hydro jelly as well.

Once frozen, a hydro jelly will stay in that state forever. Some hydro jellies are already found pre-frozen. When one is destroyed, a notification will appear on-screen saying "Hydro jelly burst." For hydro jellies that contain large objects in them, it will be possible to see the object protruding out.