Treat and Trick

You can take 1 hour to create a treat of some kind and sprinkle it with gold dust. During this process you choose a spell that requires the target to make a Constitution/Wisdon/Intelligence/Charisma Saving Throw and store it in the treat. You need to cast the relevant spell as part of casting this spell. 

When a creature consumes the treat, the spell effect is triggered, giving the target disadvantage on the relevant Saving Throw.

This spell is dispelled when you take a long rest.