Steam Cloud Balloon
From the Super Mario Wiki
The Steam Cloud Balloon was a hot-air balloon which could disguise itself as a cloud thanks to a special steam machine that Luigi had installed in it.
The Steam Cloud Balloon only appeared in The Adventures of Super Mario Bros. 3 episode "Mind Your Mummy Mommy, Mario". Needing a way to approach Castle Koopa unnoticed, Raccoon Luigi towed the Steam Cloud Balloon through Dark Land towards the castle, while Princess Toadstool and Toad rode in it.
The Steam Cloud Balloon was destroyed when it got sucked up by a Mushroom Kingdom Twister, and was hurled into a tower of the castle. This was a huge loss on the group's part, as they had been planning to use the balloon to escape from the castle with Prince Mushroomkhamen's stolen mummy case.
Although the Steam Cloud Balloon couldn't be rebuilt, Luigi succeeded in reusing the broken parts to construct his own Steam-Powered Mummy Sled, which he, Princess Toadstool and Toad rode on with the mummy case to escape from Castle Koopa.