JoJo's Bizarre Adventure: Part 3--Stardust Crusaders Vol 6

From the VIZ Media edition

The Arabian Nightmare To eliminate the "Lovers" Stand within Joseph Joestar's body, Polnareff and Kakyoin shrink their Stands to microscopic size, for a fantastic voyage into Joseph Joestar's brain tissue! Then, the heroes cross the Arabian desert on camelback, braving searing heat by day and deadly dreams by night...

Source: Anime News Network Encyclopedia