Tennessine is a transactinide with a half life of 51 milliseconds. It might have more stable isotopes, however production of Tennessine is very expensive as it requires other rare elements. It’s tied with the Tennessee Cave Salamander, a Salamander native to Tennessee.
Oganesson is the last animal and elements for this series. Named after Yuri Tsolakovich Oganessian it is probably a solid radioactive element that is radioactive. Unlike its Nobel Gas forebears further up the periodic table, Oganesson isn’t likely to be non reactive. Only 4 or so atoms of Oganesson have ever been produced.
Cats are one of the most wonderfully adaptive animals. The Domestic cat is extremely good at hunting, and survival in even fairly extreme condition. It’s very adapt at desert survival and will likely outlast the end of the human they are tied to Oganesson for this reason. This is also why their is a clock in this picture, the clock is near midnight, near the time when climate change and war drives humanity into a spiral of self destruction, leaving cats to take our place.