Mutilate is a verb that means to injure or ruin, usually in a brutal or messy way. If you drop a cantaloupe into a wood chipper, you'll mutilate that poor melon, with chunks of fruit and rind flying everywhere.
Mutilate can also mean altering an object so it's unrecognizable. Once you mutilate something, it'll no longer resemble its original form. Celebrities who get too much plastic surgery are said to mutilate their faces, because they no longer look like themselves. Mutilate can also describe causing a disfiguring injury. Monsters and evil villains in horror movies tend to mutilate their victims instead of neatly murdering them.