Kryptonite is one of the Foundation Elements in LEGO Dimensions 2: The Rise of Enoch, from the DC Comics franchise.
Background
Kryptonite is often used as a weapon, by Lex Luthor as he is obsessed with killing Superman, proving the Man of Steel is evil and make himself ruler. Kryptonite is Superman's only weakness making it the target if anyone wanting to take down Superman.
Dimensions Crisis
Kryptonite is seen during the Prologue and has been stolen by Bane in an attempt to take down Superman. Batman and Robin are chasing Bane in an attempt to retrieve the Kryptonite however Bane drops some which Robin grabs. The dimensional rift opens carrying Robin to Foundation Prime along with the Kryptonite which Lord Vortech adds to his collection and captures Robin.