Pond Sprites spawn when water has high levels of miasma. They're incredibly shy and can often be found hiding underneath lotus leaves. If you've ever seen one moving across the water, it is likely you have been in the presence of one of these round creatures.
Researchers believe the tainted waters feel rejuvenating to them, balancing their miasma levels so they can continue to exist. These creatures, although cute, are toxic to humans. Just being in the water with them can cause a rash.