Lanthanide

You wouldn't like Actinide, he's my evil twin brother.

I was disappointed that P-Body doesn't get to choose Lanthanum as his favourite element.

I like your name because it is a compilation of the fifteen rare earth elements with atomic numbers ranging from 57 to 71. Perhaps you picked it because of this, or perhaps you picked it because it sounded cool. Doesn't matter to me; I still like it. I hope your twin brother (if you even have one) joins this site (unless he already has) with the name Actinide. That would make my day, I assure you. In fact, I'm going to search for the name Actinide and see what I come up with. Thanks, by the way!