I also have this mug, I got it as a gift and immediately recognized it as one of those designs that gets hawked all the time by merch spammers on reddit so I checked and the only place you can buy it from that isn’t a redbubble-style site (where anybody can upload stolen designs to print on demand) - or a sketchy site that only sells a single item - seems to be lookhuman, so I assume it’s their design.