Kel Mitchell is looking back on his long friendship with Coolio, just one day after the rapper's unexpected death.ET's Kevin Frazier spoke with Mitchell about Coolio crafting the theme song for his and Kenan Thompson's Nickelodeon show, , and the way he found out about the «Gangsta's Paradise» rapper's death.«I was here at the house with the kids, and I was on social media, and I saw under someone else's page like, 'Oh yeah, RIP Coolio,' and I'm like 'Wait, wait, wait,'» Mitchell explained. «I said, 'Hold on,' and then I started looking around and saw it was true.»He continued, «Then my phone started blowing up, and everybody hit me up about it.»Coolio — who was born Artis Leon Ivey Jr.