On this interesting note I think grenades should be able to have this feature.
https://answers.yahoo.com/question/index?qid=20080802175346AADN2iS
- Put the pin back in once its pulled
- Randomized time between 3-5 seconds
- Cancel all sounds and replace it with a ringing noise
- Have a sound when the pin is pulled (Grenade spell activated)
https://answers.yahoo.com/question/index?qid=20080802175346AADN2iS