Yeah, there should be a "roll a 1 on a d20, fail your save, and you just die a horrible death 9 days later"
It's actually worse as-is. Everyone in range who fails that con check twice just dies ( 6 exhaustion == death)
And yet still less awful than a Deck of Many Things.
In my previous campaign, we had a segment with the deck of many things. My character drew the card that gave him 3 wishes. Next character drew a card and it was bad, so I wished he could have stopped that other character from drawing from the deck.
DM decides my character's wish puts him back at the beginning of the scene, so he gets to draw the card with 3 wishes again.
Spent the rest of the campaign very carefully choosing what to spend my 5 wishes on.
"Fiend pact warlock? No, you misheard- I took Pact of the Demon Core"
Now, THIS is homebrew i can get behind
I can get behind [a lead wall]
Wouldn't the damage start hours later?
What is that in the pic?
Dam, that scary
Demon core on swingy stick
Yeah, talk about cursed items
1d20 isn't that good of a damage die, even if it sounds scary because of its high maximum. Lots of smaller dice more reliably do higher damage, so I would have made it, say, 6d6 to make it sound more demonic too. 
What makes it dangerous is the exhaustion also the 1D20 isnt its damage roll but its additional effect roll.
When your aligment is Posadist Neutral
When your character is a one-winged Pixy.
