Mateo is a tall male humanoid robot with light skin, purple hair, blue eyes, and purple forearms with white hands (Mateo's purple forearms with white hands can turn into purple arm cannons). Mateo wears goggles with blue lenses and blue straps and white rims, a purple sleeveless polo neck, purple pants with a blue belt, and purple shoes with white socks. Mateo can shoot purple plasma out of one of his arm cannons, but at a very fast rate of fire. Mateo's purple plasma is smaller than Eric's pink plasma. Unlike Eric's plasma, Mateo's plasma cannot travel through some things that would normally stop projectiles (some examples include solid platforms, or spikes) (without damaging some things that would normally stop projectiles (some examples include solid platforms, or spikes)), which stop Mateo's plasma and don't stop Eric's plasma. Mateo's plasma can still hit enemies, bosses, or wooden crates (whilst damaging enemies, bosses, or wooden crates), which stop Mateo's plasma. Mateo can shoot his purple plasma at a very fast rate of fire. Mateo can also shoot a purple laser out of one of his arm cannons that travels very fast, but he needs secondary fire ammo (which can be regenerated by collecting light-green stars in "Eric & Yannik X", and in "Eric & Yannik 5", secondary fire ammo gradually regenerates on its own, no light-green stars required) to shoot said laser. Mateo has high defense with low offense and mobility.