How does the ghostly vendor know that the buried person still had their skull right there.

That's because it was the ghostly vendor's own skull and they checked.

Fine he'll get the skull but only because the owner of the skull seems to be fine with it and also not be missing it and also it was duplicated somehow?? And also it's kinda cool.

Excellent! That'll be §500.

...really? The Sixam owl over here is §100 though.

Well, you see, the skull is one-of-a-kind.

Uh huh. And how long has the vendor held onto this skull for without managing to sell it.

Well, uh...

You know what, never mind, Peter thinks he'll just get the owl. Actually, no, he'll just learn the familiar spell himself and go enchant his cat—

W-wait, hold on! Uhhhh how about a discount? Since Peter seems like such a nice fellow and all. The skull will go for §250, that's a 50% discount!

...§200? Come on, man, they've got to make a living, here, pun unintended.

§150.

§175!

Sure, but just 'cause skulls are cool and Peter wants to be unique.

Deal! Pleasure doing business. Here's this little magic crystal ball on a pedestal.

...what does he do with it.

He binds the familiar to himself, of course.

Of course, how silly of him.

Is it... obvious... how to do that?

Yeah, reasonably so.

Alright, then, sure, why not.

The crystal ball glows and then disappears.

Hm. And can he then, uh, summon his familiar somehow?

Yeah! Here's a floating, stylized skull without the jawbone with glowing green eyes and glowing green mist surrounding it.

"Hello!" it says. Somehow.

"—oh you can talk."