Poisoned turd
Related to the term poisoned chalice (meaning something initially appearing good that later turns out to be a burden), a poisoned turd is something unpleasant that you have been forced to do/accept which later to turns out to be much worse than it initially seemed
James: When Tom got me to do that presentation for him, he neglected to mention that the entire departmental staff would be present and that the data were from the wrong fiscal quarter
Betty: Wow he handed you a real poisoned turd
Betty: Wow he handed you a real poisoned turd