thejaxster
Skeletron
Go to you account name at the top right of this page, hover your mouse over the name and click personal details. It is the drop-down right under your profile avatar. As @Danoh23 posted you need to have earned the trophy for the title. From the drop-down you can pick what you want. Hope this helps.I think the Traveling Merchant doesn't sell an Extendo Grip. I used the bug (where when you exit and go back the items are different) and did this like 50 times (he spawned 3 times in total). I don't really need it but its the only item i dont have from the Traveling merchant.
P.S. How do you change your profile from terrarian to like skeletron (this forum profile)?