i don't know if i necessarily had a childhood (i consider myself an ageless entity in regards to my actual self, so a "childhood" is an odd concept to me) but i do remember things from before kris opened the dark fountain.
...... it was really boring most of the time, just sitting around being a normal tv. though i did enjoy being an entertainment source whenever the dreemurrs and sometimes the holidays would watch the shows and movies that were on, eventually, as you might know, people began to watch me less and less, i don't really want to talk about the details of that though. i was shut off for the last time one day and then it was just. nothing. i couldn't see, i couldn't hear, i had lost any senses i had. i was conscious still but there was nothing else. for what might've been years, things were just like that. i stopped being able to think properly at some point. but then suddenly, i remember being on a dark stage, one VERY similar to the one on tv time. there wasn't any lights or noise or anyone around. this was the first time i had a body/my dark world form. this was when the roaring knight had appeared and told me the whole thing about creating an endless show and having all the people watch me as i wanted. this entire encounter was honestly VERY scary (have you SEEN the knight??? that guy is SCARY in person if you actually meet them) but i went along with the whole show thing. cue entirety of chapter 3, then me being brought to castle town. that was where i stayed instead of being brought to mettaton's house. i had decided i actually liked being in castle town. though i do vaguely remember some random things from after this, my memories are mostly blurry to this point.