The Prize D-Spenser in Mouse: P.I. For Hire is a locked cabinet inside the Little & Big Bar, over the road from your private investigation office. If you approach it, on-screen text explains that you need 20 prize tokens to open it and reap the rewards within. That’s a lot of tokens though, and to earn them, you must win at baseball cards, against the opponent at the other end of the bar.
To help you decide whether it’s worth it or not, we’ve got the details of what you get from the Mouse: P.I. For Hire Prize D-Spenser once you’ve accumulated 20 tokens. Minor spoilers below, of course.
Mouse: P.I. For Hire Prize D-Spenser reward explained
Once you’ve earned 20 tokens from winning at baseball cards, opening the Prize D-Spenser will reward you with the X1 D-Mousifier. This is, for all intents and purposes, a ray gun in that classic sci-fi style. It deals considerable damage per shot, and once you upgrade it with schematics, you unlock its alternate fire mode, which is a steady laser beam, especially good for taking down bosses. Unlocking it also rewards you with the “Everybody Loves Rayguns” trophy/achievement, which describes the X1 D-Mousifier as Spike-D’s “exclusive gun of sorts.”
Is it worth spending the time to unlock? That all depends on how much you enjoy the baseball cards minigame. The gun isn’t so powerful that it blows the rest of your arsenal out of the water, but it is another solid option, and it’s a little more imaginative than your standard pistol, James Gun, shotgun, etc. Playing baseball cards can get very monotonous though, so you’re not missing out on too much if you decide not to bother going for it.