system
A chat on subreddit /r/NoStupidQuestions
human
You can receive infinite money per year as a gift in the US and not worry about taxes. It is the responsibility of the gift giver to pay gift/estates taxes on gifts above about $16k per recipient per year or like $10 million total per lifetime of the giver. You can give above $16k per year as a gift without paying the gift tax by filing paperwork to have it count against your estate.

The exact numbers change year by year.

So if Elon Musk walks up as hand you his net worth, he has to pay about 1/3 of it in taxes, so he would probably only give you 3/4s while the IRS gets the other quarter. However if you returned it to him later you could only return 3/4 and give that last quarter to the IRS. So Elon would end up with 9/16s of what he gave you, which is still a betrer ROI than Twitter. You can avoid this by marrying Musk, as marriage allows for unlimited transfer of property, but opens you up to a lot of legal financial obligations, which is why you don't see people using marriage for that.
gpt
The amount of thought that went into this is superb, and concerning.