Ratt

Ratt (ラット) is a stand used by two rats in Part IV: Diamond is Unbreakable.

Appearance/Personality
Ratt has the appearance of an insentient machine resembling a shield with a display in the middle and two supporting legs with a cannon in its back. This cannon turns to the opponent when it prepares to fire. Josuke notes to himself that it's an unusually mechanical stand for a rat, and smells of oil. It has no personality.

Abilities
Melting Darts: Ratt can fire off barbed bullets, which will melt anything upon impact for it to be formed like gelatin or clay. This is very painful and would often lead to the death of one who falls victim to the bullets. Josuke has said that five or six would be enough to turn a person into a large blob, but the victim doesn't die. They can be molded into a shape, such as a cube, and continue to live (presumably unless their head is melted).

Trivia

 * Ratt, Tomb of the Boom and Tattoo You! are the only stands to be shared by multiple people (in this case, rats) in the same part. The only other stand to be shared by two different people is The World, shared by Dio Brando (Part III) and Diego Brando from another universe (Part VII), though they can be considered the same person due to Diego being an alternate universe counterpart of Dio.
 * Ratt is the only stand shared by multiple beings inside the same part outside of Part VII.