It’s actual Great Old One mouthfuls of madness.
This is a tagless cotton t-shirt that ships to most places from the United States. It has the ‘Beastros’ logo on the back.
The designer is Jeff Schuetze who is an animator and storyboard artist who has worked for the likes of College Humor, Rooster Teeth and the CW.
If you like this style, then check out his webcomic Jefbot which is something of an autobiography but currently has a cyborg bear doing battle on the home page. Start here if you are a new reader, as it might be a kinder place to begin.