Masha (マシャ Masha?) is a robot created by Ryou to detect chimera animas and mew aqua. Originally called by her model number of R2000, Ichigo renames her "Masha" after her crush Masaya. Masha likes the new name and likes being with Ichigo. After the aliens are defeated, Masha chooses to stay with Ichigo when Ichigo goes to London with Masaya. In addition to detecting the chimera animas, Masha eats the jelly-fish like parasites that come out of the victims after the Mew Mews defeat them. When the Mew Mews defeat a Chimera Anima, Masha eats the jellyfish-like parasites that come out of the infected animals, plants, and humans. She can also merge with mew aqua found by the Mew Mews to transform into the Mew Aqua Rod, allowing the Mew Mew to perform the Ribbon Aqua Drops healing attack. Masha does not have the capability for high level speech, primarily saying "pi" and "tweet." She is occasionally shown saying regular words, with the most advanced being seen in Tokyo Mew Mew a la Mode where she says "Masha is going with Ichigo!"

Masha is the only character in the series to also appear in Mia Ikumi's short story, Tokyo Black Cat Girl, which would eventually become Tokyo Mew Mew. Though Masha has the same name and general appearance in both series, in Tokyo Black Cat Girl he is a very different character. Instead of being a robot, Masha is an intergalactic police officer who partners with Princess Azumi to defeat alien parasites called the Baku. He is male instead of female, has the ability to change disguise himself as a cell phone mascot, can speak in complete sentences, and is capable of fighting the Baku in small numbers.

In the Tokyo Mew Mew anime adaptation, Masha is changed to a male character. He is capable of speaking in short sentences and he is shown trying to help the Mew Mews when they fight. In the original Japanese series, he is voiced by is Junko Noda. In the Mew Mew Power English adaptation, his name is changed to Mini-Mew and he is voiced by Tom Wayland.

(Source: Wikipedia)