Concert season is in full swing, but a new villain is hurting the experience for many: superfans seeking five minutes of social-media fame. Homemade signs, screaming teenagers and bouncing beach balls aren’t new to concerts. What has changed is that, largely thanks to TikTok, any moment of a concert can go viral. More fans are trying to force that moment to happen with wild shenanigans, annoying noises or demands on artists to play unusual songs.