"This guy needs to eff off or I will hunt him down," the singer tweeted at the end of January. Yesterday, the businessman (who currently faces securities fraud charges) returned fire, tweeting "chill bae."

Shkreli drew global attention and ire for his manipulation of life-saving drug costs, but his infamy has frequently intersected with the music industry. He paid $2 million for the latest Wu-Tang Clan album and has leveraged his love of rap into a bizarre social media presence.