Ryan and Dave, two identical twins, have a very weird idea of extreme body modifications. Here's what they say in an interview with Body Modification Ezine:
RYAN: After discussing and thinking about it very seriously for about a year, we decided to take the big step. To put it simply, Dave had his entire right arm (since we're left handed) amputated at the shoulder and we surgically reattached it immediately behind my right pectoral muscle.
UPDATE: It's an April Fools Joke, everybody - Please don't propagate story as true (like I did).