EoinGhost here. I noted that some people, most on Tumblr, thinks Jeff's last name is spelled R-a-n-d-a-l-l. However, they got it wrong. His last name is spelled R-a-n-d-e-l-l. "Randell". There an E between the D and the L, not another A. If you don't believe me, here's some proof. I put captions on my TV and on Amazon.com when I was watching Average Jeff and this is how it was spelled out.
And if you look really closely at the title card of Jeff's New Toy, you see his full name on the delivery sticker on the box.
For the last time, Jeff's last name is Randell, with an E!