X.A.N.A.-Odd is the Polymorphic Clone of Odd seen in the episodes X.A.N.A.'s Kiss and Revelation. The clone acted very much like how Odd would act if he was in a bad mood. However, unlike the real Odd, his pupils are a bit smaller, like they were in the first season. It took on Ulrich's form in Revelation after Ulrich saw through the X.A.N.A.-Odd's disguise. In X.A.N.A.'s Kiss, the polymorphic clone took the shape of Odd after the real Odd tells the clone to do a favor for him and take the shape of a wimp, mocking him.
X.A.N.A.-Odd had the ability to shoot a consistent stream of arrows from within his arrow launchers.
It is shown by its appearance in Revelation that a spectre on Lyoko will not disappear even if its tower is deactivated after its virtualised. (Curiously if this applies to possession it would explain William's near permanent X.A.N.A.fication in Season 4)