Here’s a very mean practical-joke to pull on the IC.
Take an old hard drive and wipe it clean.
Then mail it to them with no explanation whatsoever.
It will drive them nuts, they will spend a lot of time playing with the new toy.
Better yet, send them a hard drive that was wiped with BleachBit and then formatted in NTFS. Add 4 or 5 large encrypted files with scrypt and each an encryption of and already encrypted all with different random passwords. That would keep them busy for quite a while running hash after hash.
Good Hunting... from Varmint Al