Fireproof Lava Boat
From the Super Mario Wiki
The Fireproof Lava Boat (also known as the Fire Proof Boat) is a small, inflatable and apparently heat- and lava-proof raft owned by King Koopa.
In The Super Mario Bros. Super Show! episode "Too Hot to Handle", King Koopa, after capturing Princess Toadstool, had his Shy Guy minions begin the inflation of the Fireproof Lava Boat, which King Koopa planned to leave the island of Waki-Waki with, with bellows.
After being told by Fryguy that Mario and Luigi had clogged his Lava Machine, which began to back-up and spew lava everywhere, King Koopa fled to the raft with Princess Toadstool to escape the lava machine before it destroyed him. Seeing King Koopa approaching, Mario, who had hid himself in the raft with Luigi, threw the Fireproof Lava Boat's life preserver in King Koopa's path; getting his foot caught in this life preserver, King Koopa was tripped by Mario, who pulled the rope attached to the preserver. Once he tripped, King Koopa relinquished his grasp on Princess Toadstool, who was sent sailing through the air, only to land in Luigi's arms in the raft.
After the lava machine exploded and sent lava everywhere, Mario, Luigi, Princess Toadstool and Toad, who Mario brought aboard the raft with the life preserver, used the raft to ride a wave of lava out of the volcano they were in. It is unknown what they did with the raft after they were flung with it out of the volcano on to the beach of Waki-Waki.