Call it the anti-Ice Bucket Challenge.

Rapper 50 cent took to Instagram Thursday to issue a rather unusual challenge to boxing champ, Floyd Mayweather.

Improvising on the ubiquitous Ice Bucket Challenge, the rapper vowed to donate $750,000 to a charity of Mayweather’s choice if the boxer reads an entire page from a Harry Potter book “out loud without starting and stopping or f__king up.”

“Floyd will you accept my ALS/ESL challenge,” 50 Cent says in the Instagram video, suggesting the boxer would have trouble accomplishing the feat.

50 Cent ends his profane rant by tossing a bucket of ice over a balcony.

While the challenge appears to be in good fun, a history of online jabs between 50 Cent and Mayweather has fuelled speculation there’s some bad blood between the two stars.

Whether Mayweather accepts the Harry Potter challenge, he’s not necessarily exempt from the popular Ice Bucket Challenge now making the social media rounds. Also on Thursday, famed illusionist Criss Angel took to Twitter to challenge Mayweather, Shaquille O’Neal and Cirque du Soleil co-founder Guy Laliberte to follow his lead, and take up the chilly challenge in aid of awareness and fundraising for amyotrophic lateral sclerosis.