It's a parody of overserious memes that are trying to sound edgy and badass. The archetype is a gun-wielding skeleton that's riding a motorcycle and saying something about thin blue lines, but wolves and other imagery are also adjacent.
Instead, THE_PACK takes that aesthetic, cranks it up to 12, and adds some silly text. Everyone is role-playing as a skeleton that's obsessed with motorcycles (hogs). You have to TALK IN ALL CAPS to be heard over the engine noise. And everyone's friendly and welcoming in a way that edgelords aren't.