Roentgenium is one of the more interesting transactinides in that it has in what little experiments that have been carried out on it behaved like gold. Although this isn’t entirely surprising as it would be expected as gold is directly above it in the periodic table. It’s highly radioactive and has a shortish half life, but might have more stable isotopes.
Drugstore beetles are one of the most expensive beetles known to man, not in their beetle state though. Their larvae can eat through even lead in desperate times. The eggs will spread quickly piggybacking on yeast spores and decimate any stores in a matter of weeks. They particularly like strychnine but also happily eat hair, leather, parchment, leather and books. So they are not good news for a library. They are tied to Roentgenium because of it’s danger and stark beauty.
Copernicium that has been produced has short half life of 25 seconds. Again a transactinide that is predicted to behave like zinc or mercury, if a more stable isotopes can exist. Deer scatter when scared and I felt somehow that this made them a good match.