Radium-226

When Radium-226 enters, each opponent gain a poison counter.

Half-Life:After 1600 years, create token Radon-Gas with Decay and: As long as Radon-Gas is on he battlefield, each opponent gain one poison counter every upkeep.

Discovered: If anyone other than you cast Pierre and Marie, Discoverer of Radium, they gain control of this artifact.

"We'll name it Radium!"