U-Boat Ultimate

U-Boat Ultimate (UボートアルティメットU bōtoarutimetto) also known has Das Boot Ultimate (ダスブーツアルティメットDasubūtsuarutimetto) is the improved and more enhanced version of U-Boat, created by Kars. It is featured in the light novel JORGE JOESTAR as one of the Stands in the 37th universe.

Appearance
Other than Narancia's version, U-Boat Ultimate appears as a more advanced submarine-like design with no antennae. It has jet engines at the front with floatplanes on the side. It does not have any torpedo tubes like the original U-Boat, and it has a round nose.

Advanced Sonar System
U-Boat Ultimate is able to produce a high-frequency noise through one's body. This is shown when Kars uses the Stand to produce an explosive-like sound on Pucci and Joji, the sound still rings in their ears even after Kars had stopped.