It's referring to people impersonating him and offering a multiple of the amount that someone transfers to them. (A bit like the Nigerian Prince scheme).

Here's the first example I could find, the scammers are impersonating Elon Musk in this case:

https://twitter.com/88kboss/status/1030003844497989633

It is a joke on Ethereum giveaway scams (with scammers pretending to be celebs) and giving zero f*cks.