Puddle Spore

Puddle Spores are creatures that float in lava with their shells tightly closed most of the time. When an predator approaches one, it will open its shell in an attempt to make itself appear larger than it really is. If the predator continues to appraoch, then the Puddle Spore will slam shut and eject a spread of harmful energy globules. Its shell is impenetrable and emits a foul smell.

Samus encounters them in Magmoor Caverns on Tallon IV. When she approaches them, they open their shells. Samus can then fire at them with a beam to cause them to flip over, allowing her to step on their under-bellies. They pose no threat other than the energy globules they emit when they close their shell.