50 Cent explained the terms in his Instagram caption on Thursday, writing: "Floyd will you except my ALS/ESL CHALLENGE: I will donate $750k to a charity of your choice, If you can read a full page out of a Harry Potter book out loud without starting and stopping or f**king up. lmao."
Fueling the feud, he then posted a pic of Mayweather, 37, with the caption: "DAMN I CAN'T READ THAT WHOLE PAGE NOW. f**k you 50, Lmao."
Late-night host Jimmy Kimmel caught wind of this challenge and is looking to televise it. The rapper also broke this news via Instagram, telling his 2.8 million followers: "Just in people, Jimmy Kimmel will let Floyd read live on his show if he accepts."
Here's hoping Mayweather is a fan of J.K. Rowling's wizard world.
In the meantime, check out another musician, Garth Brooks, taking part in the ALS Ice Bucket Challenge: