**Description:** Translucent, bell-shaped creatures about the size of a penny; a non-native but widely naturalized freshwater species.
**Size:** 0.2 to 1 inch in diameter.
**Behavior:** Populations are "boom and bust," appearing by the thousands during hot, dry Augusts. They are harmless to humans.
**Identification:** Look for a pulsating, clear "umbrella" with a white cross-shaped structure in the center.
**Habitat:** Appears sporadically in the calm, warm coves of the Allegheny Reservoir.