Blue Kryptonite

A form of Kryptonite that is harmless to both Kryptonians and humans but which is deadly to all Bizarro creatures.

Blue Kryptonite is actually an imperfect duplicate of green Kryptonite created by the same duplicator ray that creates Bizarros. Any Bizarro exposed to blue Kryptonite will slowly weaken and eventualy die if the exposure continues. In 1960 the Bizarro-Supergirl was killed by blue Kryptonite exposure (S No. 140).

Unlike other formes of Kryptonite, blue Kryptonite radiation is not blocked by ordinary lead. However, an imperfect duplicate of lead created with the bizarro ray will block blue Kryptonite radiation

In November 1961 a race a blue Kryptonite creatures who lived inside the Bizarro world of Htrae invade the surface of the planet. (Adventure Comics No. 291)

One apparently apocryphal account has Bizarro #1 killing himself with a small piece of blue Krpytonite so he could be a perfect imperfect duplicate of Superman. This was necessary Bizarro reasoned since Superman was alive, he should be dead. (S No. 423: Seotember 1986, "What Ever Happened To the Man of Tomorrow?"