Vento Aureo - Chapter 50 
As Narancia and Giorno start rapidly aging, Mista begins to panic. Bucciarati orders him to calm down, saying that the enemy couldn't have found them yet. Bucciarati gives Mista two options, either escape the train with Trish, or kill the Stand user. Mista picks the latter option, believing it would be simpler. As they watch Narancia beginning to deteriorate, Mista starts to exit the turtle, but is stopped by Giorno. Giorno states that they must learn how the Stand works. The enemies can't kill Trish, so there must be a way to differentiate between male and female.
Giorno deduces that the aging process is determined by body temperature. Due to fats, women's body temperature changes at a slower pace, and because Mista and Bucciarati have been drinking cold drinks, their body temperature is cooler. To prove this, Trish places an ice cube on Narancia, and his skin starts reverting back.
Mista takes the remaining ice cubes and exits the turtle. In the train's control room, Mista tries to turn on the air conditioning, but is ambushed by Pesci's Beach Boy. Mista realizes that there are two Stands he must defeat.