For Hayden Shock, who was born deaf, Terrible Towels are in-game closed captions.

“When the fans wave their Terrible Towels, it's a visual effect of cheering for me. …I always get goosebumps when I see the Terrible Towel.”

On the towel and its magic ⤵️

https://www.espn.com/nfl/story/_/id/42490881/pittsburgh-steelers-fans-not-rattled-anti-terrible-towels