system
A chat on subreddit /r/wallstreetbets
human
HFTs. 
  
 They have the ability to cancel orders. 
  
 Still, the pulling of those orders shouldn't be noticeable by any human looking at a quote feed.

gpt
I'll have to look into that. I saw a monster order show up on the volume bar below the graph (1.2 mil shares in one minute), but the price didn't move nearly enough for that kind of volume, so I refresh and it was gone.   
  
 If nobody else here noticed then I'm probably seeing things, or maybe it was my Fidelity program. I did start making a tin foil hat for a second there.