These are the items the Sleer guards while it waits for its master. They seem to be signs of greed, and the Sleer is also a greedy being. For a minute, the Sleer seems like it’s extremely loyal, but we think that's just a trick. Check out what it tells Bod:
IF YOU WERE OUR MASTER, WE COULD HOLD YOU IN OUR COILS FOREVER. IF YOU WERE OUR MASTER, WE WOULD KEEP YOU SAFE AND PROTECT YOU UNTIL THE END OF TIME AND NEVER LET YOU ENDURE THE DANGERS OF THIS WORLD. (7.319)
When you look closer, it seems like the Sleer is simply greedy and wants to keep the master all to itself. As Jack Frost finds out, this is no fun at all. So, if the Sleer is greedy, it makes sense that the items he guards are symbolic of greed. There’s something greedy about having your treasure buried with you anyway, which could be a point the ever-sly Neil Gaiman is trying to make.
When Abanazer Bolger and his friend Tom see the brooch, they’re overwhelmed with greed, to the point where they try to kill each other. These guys were greedy anyway, but the brooch magnifies their greed to a whole new level.
Now, think about Jack Frost. He gets awfully greedy when he catches a glimpse of the Sleer’s treasure. It’s almost too easy for Bod to trick Jack, which shows that greed is his main weakness, the weakness that leads to his downfall. He’s not just greedy for this treasure himself, though – he sees the Sleer’s lair as the perfect place for the Jacks to have their ceremonies. And he wants to have his first ceremony right now. Here’s what we think his plan is:
A. Slit Bod’s throat with the knife.
B. Make sure the blood lands in the cup.
C. Drink the blood.
D. Pin the brooch to the lapel of his fancy suit and dance around to his favorite Justin Timberlake song.
OK, we’re serious about A through C, but we have no idea what he planned to do with the brooch or how it fits in with Jack’s idea of a ceremony. And it doesn’t really matter either, because Jack’s greed stops him from being able to do any of that. When he, out of greed, agrees to be the Sleer’s master, the game ends.