I am a Uranium-based organism. My skin is so hard it doesn't hurt me.
Oops. Forgot to make situation.
The next user discovers a new element. However, when they put it in a particle accelerator, they realize it is too late. The element is extremely fissile, with 10 times the power of Plutonium the same size. And you just launched a neutron into it.
Fortunately, the magnetic field of the particle accelerator directs the fission fragments into a high speed collision, where I produce the Higgs boson.
The next user discovers a new form of matter that causes black holes when it touches regular matter.