The poem opens with a command that works against itself: "Try not to think about" something. Of course, the moment you're told that, you think about it. What follows is a deliberately absurd picture: three Elvis impersonators who turn into motorcycles and pizza ovens, and who have fruit for hands that grow back after being eaten.
The speaker doesn't explain or justify any of this. The tone is deadpan, almost like a calm instruction, which makes the strangeness funnier. The title, which names what looks like an old steam-powered vehicle, adds to the oddness, since it has no obvious connection to the images that follow. Judging by the poem alone, the speaker seems to enjoy planting an image you can't shake.
The mood is playful and surreal. There's a faint undertone of unease, too, in the idea of hands that are eaten and return, but the poem mostly invites you to laugh and let your imagination run wild.