Musk bought like 10% of Twitter stock
Stock rose 25%. It went down a bit in the following days, but is still up significantly.
A few days earlier he engaged with the public on his Twitter, asking about if Twitter respects democracy and stuff and what should be done, and people wondered if he might buy a majority in Twitter for a few billion.
A few days after buying his 10% in stoc, he offered to buy all of Twitter for like $40b or something. It wasn't accepted. News is discussing it.