I need to know what the Bob Velseb animation actually is

I'm not sure if the topic is NSFW since I don't know what the hell it contains, but I really want to know what the "Bob Velseb Twitter animation" is. Everyone talks about it like it's a boogeyman or the devil and nothing at all tells me what it entails and I can't find it to find out myself. If someone could just point me in the right direction I'd be grateful because not knowing is killing me tbh