His friend was diagnosed with ALS — Lou Gehrig’s disease — so he helped kick off what would become one of the biggest viral fundraising campaigns ever: the “Ice Bucket Challenge.”

But this weekend, while celebrating the campaign’s success, he took a fatal plunge into the waters of Nantucket.

Image via WPVI-TV

Corey Griffin. (Image via WPVI-TV)

The Boston Globe reported:

Corey Griffin was ecstatic when he called his father Friday night from Nantucket Island. The 27-year-old had just raised $100,000 to fight ALS in honor of his friend, Pete Frates, whose struggle with the disease turned the Ice Bucket Challenge into a viral sensation.

“He was the happiest guy in the world,” Corey’s father, Robert Griffin, said of his son. “He called me last night and told me he was in paradise.”

Hours later, at about 2 a.m. Saturday, Griffin dove into the water from the “Juice Guys” building on Straight Wharf, according to a statement from Nantucket police. He floated to the surface, then he sank. He did not come up again.

Griffin's friend Pete Frates, who suffers from ALS, seen at Fenway Park where he went through his own "Ice Bucket Challenge. (Image source: screengrab via Boston Globe)

Griffin’s friend Pete Frates, who suffers from ALS, seen at Fenway Park where he went through his own “Ice Bucket Challenge.” (Image source: screengrab via Boston Globe)

Griffin is survived by two siblings and his parents, the Globe reported.

“I just can’t stress enough that he was the greatest best friend, brother, and son anyone could ask for,” one of Griffin’s childhood friends told the Globe. “He lived life to the fullest and everybody loved him. And every time he walked into a room, he put a smile on everybody’s face.”

Frates and Griffin were instrumental in bringing ALS to the national spotlight with the “Ice Bucket Challenge,” widely circulating on social media, in which participants either take a bucket of ice water to the head or donate $100 to ALS research.

Celebrities from Bill Gates to Justin Timberlake have taken the frigid challenge, while President Barack Obama said he would donate money instead of being drenched.

Follow Zach Noble (@thezachnoble) on Twitter