From the Super Mario Wiki
HP Rain is a special move used by Mallow in Super Mario RPG: Legend of the Seven Stars. The spell has the ability to heal one ally. HP Rain is similar to Toadstool's special move Therapy, but it is weaker and heals less HP. Mallow learns this move at level three and it costs two FP to use.
The rain cloud bares a striking resemblance to Mokura, albeit white.
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