Use the adjective warped to describe something that's twisted or bent. If you leave a wooden kitchen chair out in the rain, it may eventually become too warped to sit on.
Something that's warped is misshapen, like a maple cutting board left to soak in the sink, or a plastic cup that melted and twisted in the hot summer sun. Colloquially, you can also use this word for anything bizarre or distorted, like your older brother's weird, warped sense of humor. The Germanic root of warped means "to turn or bend."