The first time I ever heard or saw Mastodon (the band), it was a live performance on Letterman that genuinely sucked balls. It put me off the band for about a year before I gave them a proper listen (they're now in my top 5 bands of all time). Anyway, on that first clip I saw on Letterman, I thought the bassist was Keanu Reeves and that this was another of his weird side projects. I remember thinking "stick to acting bro, this sucks".
This is the clip in question:
Fucking awful performance. But tell me that's not Keanu's twin brother on bass, perhaps after a stint of sleeping on Oscar the Grouch's couch ๐