A poisoned chalice
Definition 1 of 1
Pro Tip 1/3Hidden Consequences
Understand that this phrase implies negative outcomes that are not apparent at first. 
He thought the promotion was great, but it turned out to be a poisoned chalice.
Pro Tip 2/3Beware Offers
Be cautious if someone eagerly offers you something; it could be a poisoned chalice. 
They offered her the role without an interview, which felt like a poisoned chalice.
Pro Tip 3/3Leadership Warning
The phrase is often used to describe leadership roles that bring trouble along with prestige. 
Taking over as CEO in this climate is a poisoned chalice.