mouse
Since the mid-90s I went by the username mouse for various reasons. When I began to study esoterica this morphed into fratermus. When I retired into the desert hermit life I started using frater secessus.
the mousepad
Various iterations of my personal homepage have been called the mousepad since the mid-90s. I used to own mouse.net, back when .net meant something. I worked at an ISP so snuck it through.
~1997 the InterNIC (!) cashed my renewal check (check?) but failed to renew the name. It was picked up by a Korean company and InterNIC declined to fix the mistake, possibly due to perceived language barrier issues. After a few weeks of being domainless I registered mousetrap.net.