Acid rain
Acid rain was a form of highly acidic precipitation that fell to the ground from the atmosphere.

Murder Planet used this form of rain as a means of digesting its prey. In 2383, it doused the crew of the  in acid rain as a means of killing them. They sought cover in the remains of a Klingon Bird-of-Prey until they could continue their return to the Protostar. ()

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Meteorology