The Evolvo-Ray is Dr. Nitrus Brio's technological breakthrough that evolves any creature exposed to its beam. It gives animals human properties, such as the ability to walk upright and talk. The machine is responsible for the creation of Crash Bandicoot and the mutant animals working for Dr. Neo Cortex, who claimed credit for all the work, much to its inventor's frustration.
Cortex used a prototype as a kid on his pet parrots, Victor and Moritz, to initiate his plan of conquering the world using mutant animals. The experiment didn't go as planned, and the Evolvo-Ray ended up warping the test subjects to the Tenth Dimension, where they ended up developing super powers and a bitter resentment towards the would-be doctor, eventually becoming the Evil Twins.
Uka Uka has used the Evolvo-Ray on himself once in an effort to defeat Crash Bandicoot once and for all. It ended up giving him a tree-like body, which he lost upon defeat.