system
A chat on subreddit /r/wallstreetbets
human
Options. Check the NFLX stock price now and around christmas. On Christmas he bet 2k (bought calls) that NFLX would be over $300 again in January (or whenever his options expire). It's now way over $300 so his options are now worth a lot.

gpt
Oh options,  so not traditional stock and bond trading.