One Writer's Thoughtforms
As writers, we give a form to our thoughts, so for me a thought form might have quite a different meaning from, say, yours. It's probably different from that of the ESP lab as well, since Chas was supposed to be a formless glob of unfocused positive energy.
Another thoughtform I'll have to work on at some point is Terror's fault. See, she was still rather young then, and liked bedtime stories, and I started making them up on the fly. The protagonist was named Carrot, because he really loved to eat carrots. He was an orange dragon. ;-)
For Chas and for Carrot, the essential roots are obvious: I'm a writer, and I happen to like dragons. At some point I'm also going to write about my red headed unicorn too--well, red maned, actually, but it amounts to pretty much the same thing, lol. No, he doesn't have freckles (at least, not yet).
For every Yin, of course, you should really have a Yang in opposition. I tried that with Carrot, via the Evil Wizard, but Terror insisted on co-writing, and you know how kids are at a young age--she had Carrot become his friend and then the Evil Wizard became the Good Wizard because he'd not had a friend before, but now he had one. *grin*
Silly, right?