Bubble Fruit

Bubble Fruit are small objects with a blue center surrounded by a dark outer shell, usually found growing out of the ground around bodies of water.

Function
Bubble Fruit is unique in that it has two distinct states with different functions - dry and swollen.

Dry
Dry Bubble Fruit is practically identical to. It can be used to stun various creatures, flip over, distract sound sensitive predators, kill  and so on.

Swollen
When submerged in water for a few seconds, dry Bubble Fruit pops, expanding into a clear, gelatinous bubble. Swollen Bubble Fruit is edible, filling up 1 food pip (¼ of a food pip  as  or Artificer) when eaten. Rivulet has the ability to pop bubble fruit without submerging it in water. Akin to most other foods, swollen Bubble Fruit is part of the foreground, meaning that it reflects thrown s & Rubbish, and can be pushed around.

Trivia

 * Holding Bubble Fruit as it swells up causes it to fall out of the Slugcat's hand.
 * Swollen Bubble Fruit is squishy, changing its shape when pushed into surfaces or weighted down by other objects.
 * Dry Bubble Fruit will pop even in acid water.