Boo is a free puzzle game developed by Bart Bonte, available on Android. The game consists of dipping a pumpkin in different paints and wearing attributes to mask certain parts of the pumpkin to solve the puzzles. The game starts easy but gets more challenging as the player progresses through its 21 Halloween-themed levels, which are based on the premium app "Factory Balls". The objective is to make the correct pumpkin in each level.

The game's design and graphics are appropriate for the Halloween theme and add to the overall spooky atmosphere. The controls are intuitive and easy to use, and the sound effects and background music add to the overall experience. Completing all the levels unlocks a brand new daily puzzle mode. Overall, Boo is a fun and entertaining game that provides a good challenge for puzzle game enthusiasts. Happy Halloween!