The Mongoose was Playmaxx's mini yo-yo, with a plan. Released as a mini, with rubber O-Rings for rim weighting, it was designed to be the hub system for a set of shells that would snap onto the hub. These never materialized, as the popularity of yo-yos died down right as these were released, and Playmaxx was later purchased by Duncan.
Some Prototype String Pilot shells made it out of Playmaxx, but mainly shells from Henry's Viper were used with the Mongoose. In fact, the name Mongoose was picked as a sort of joke, because with it's superior brake pad response system, even with Viper shells the Mongoose ate Vipers for dinner.