As it turns out, someone else has had the same idea as Wanda. Except in this case the dog in question is much, much bigger.

And also happens to possess three heads.

So as Mary approaches, the big red three-headed dog bounds over towards her, barrelling forward like a hairy freight train. But right before it seems like the dog will crash into her, he stops. Looks down at the much smaller dog. And then crouches down on his front paws, butt sticking in the air as his tail wags.

"Cerberus, wait...!" Zagreus yells from somewhere behind, before quickly arriving with a quick sequences of dashes. "Sorry, he's...a bit excited. I don't think he'd have ever seen a one-headed dog before."