Plantains look like mutant, overgrown, really green bananas.
Have you ever tried to peel a green banana? They behave a lot like plantains, that is - not at all like a banana. The peel splits, emits a weird chalky smell, and if you try to eat it your mouth might recoil in horror.
Plantains are awesome vegetables. Think potato crossed with a banana, and you'll be about right. You need to cook them, and the blacker they get the riper they are. When they're solid black they're closest to bananas in flavor and texture - though they're still something I wouldn't eat raw.
How do you get into them, anyway?
Cut the ends off, cut them into chunks, cut a slit and use your thumb.