Short answers, pulled from the story.
The heavy metal band Anthrax released the extended play I'm the Man on the 2nd of May 1987. This record fundamentally altered the DNA of both genres by proving that the aggression of thrash guitar riffs could coexist with the rhythmic cadence of hip hop.
Rapper Ice-T formed the heavy metal band Body Count in 1990. The project sparked a national controversy over the lyrics of their song Cop Killer and served as a vehicle for the new hybrid sound.
Kid Rock's album Devil Without a Cause sold over 9.3 million copies in the United States. The album achieved 11-times platinum certification from the Recording Industry Association of America after the single Bawitdaba triggered a sales explosion in May 1999.
The Woodstock 1999 festival descended into chaos marked by violence, looting, and fires that shocked the nation. Critics like Jeff Brogowski of The Morning Call newspaper claimed that macho rap-metal bands were mean-spirited and that the violence was a direct result of the music's influence.
The Spanish band Proyecto Eskhata debuted on the 12th of 2012. They brought a fusion of progressive rock and rap metal that journalists described as progressive rap metal.
The 14th of 2014 marked the emergence of trap metal with artists like Bones, Scarlxrd, and OG Maco leading the charge. This new sound combined the distorted beats and hip hop flows of trap music with the harsh vocals and guitar riffs of metal and hardcore punk.