HeyItsMilly was a thing back in 2010-2013 created by the finebrothers, to explain more, they basically did asks every week or so. And well, I recently checked the channel again to rewatch for nostalgia, but I guess at same point they deleted all videos with the puppet. It was inappropriate humor, but I liked it. But I've only found clips here and there and I'm wondering if there's any anywhere else?
Was this puppet also used for gaming videos? I think that I once saw a Let's Play video of Slender Man in which the 'player' was this puppet. That was most likely in 2013 or 2014.