Up To Your Neck In Sand
Explanation: Blackbeard and other pirates of the early 18th century may be best known for making their enemies walk the plank to a watery grave, but that wasn't the only torturous trick they had up their tattered sleeves. On shore, the seafaring bandits would bury prisoners up to their necks in sand at low tide to immobilize their bodies and drown them as the waters rolled in.
MythBusters Kari Byron, Tory Belleci and Grant Imahara discovered the pirates really had killing down to a science, because without the incoming tide, the prisoners could potentially dig themselves out of the holes. Buried to his neck in dry sand, Tory successfully clawed his way to safety after an hour and a half of struggling.
But when they entombed Grant in high-density wet sand, he wasn't so lucky. Any time the MythBuster created an opening in the heavy sand, water instantly pushed more sand into the gaps. That way, escape from the rising tide proved impossible, spelling out a death sentence for any sand-logged prisoner and confirming ye olde pirate myth.