From Ovid’s Metamophoses, the transformation of the nymph Arethusa into a river.
“The God so near, a chilly sweat possest
My fainting limbs, at ev’ry pore exprest;
My strength distill’d in drops, my hair in dew,
My form was chang’d, and all my substance new.
Each motion was a stream, and my whole frame
Turn’d to a fount, which still preserves my name.” (Ovid, Metamorphoses, 5.710)
But I think Wikipedia says it better:
“She began to perspire profusely from fear, and soon transformed into a stream.”