The Equation Keystone is one of the 10 Keystones that exist in Lego Dimensions 2: The Rise of Enoch.
It is an purple transparent oval shield with the plus sign on the upper center, the multiplication sign in the lower center, the equals sign in the right-center, the division sign at the left-center, and the minifigure head and infinite symbol in the center.
When used, the player can target his/her ally, clone them with the player deciding how many clones to spawn as long as the number of clones is up to 13. This keystone can help the players to solve puzzles as well. The player can also clone Lego bricks and leave them on the ground to let master builder characters to build something out of the blocks.