Ferris the crab. Ferris is the unofficial mascot of the Rust Programming Language.
Many Rust programmers call themselves "Rustaceans", a play on the word "crustacean". Crustacean are a family of animals that include crabs, lobsters, crayfish, shrimp, krill and barnacles.
Ferris is a name playing off of the adjective "ferrous", meaning of or pertaining to iron. Since Rust often forms on iron it seemed like a fun origin for the mascot’s name.