Bohrium is a very unstable radioactive transactinide element that can only be produced synthetically like all of the elements above 100. Only limited experiments have been performed on Bohrium as it half-life is barely a minute long.
Megascolides australis is a giant earthworm that makes a thumping noise in response to noise above them. Much like Bohrium, they are rare and secluded.
Hassium is so unstable that only about 100 atoms of it have been created in a lab this far. It’s named after the German state of Hesse.
Giant Sloths used to live throughout most of the American continent. Now, unfortunately, they are extinct but they did eat Avocado and spread their seed, Hass is a common verity of avocado and it rhymed with Hassium so that was why I chose it to represent Hassium.