time bomb

noun3

1. •
   A bomb that has a mechanism such that detonation can be preset to a particular time.
2. •
   (figurative) A situation that threatens to have disastrous consequences at some future time.

   • Even so, they managed to morph the recent European parliamentary elections into a time bomb and plant it under their country’s own future. — 2014
3. •
   A malicious program designed to perform a destructive action at a certain date or time.

   • Donald Gene Burleson was prosecuted on felony charges for planting a time bomb that, shortly after he was fired, deleted more than 168,000 brokerage records of USPA & IRA in Fort Worth, Texas. — 1994