Gold Bar from Fort Knox

Origin
With 4,500 tons of gold stored in 7x4x2 blocks locked deep within Fort Knox. Every three months a person with security clearance goes in to count and weigh each bar to make sure no one did the impossible and broke in.

Effects
When picked up traps possessor in a 3 foot by 3 foot room, walls to the ceiling. Inescapable until neutralized or someone else becomes the victim. No one else can see the walls and others can pass through it. Walls move with the victim if an outside source moves them.

Collection
During one period of time the person, a man, never returned with the numbers. Sending a three man security team in they discovered the man sitting on the ground with a single bar in front of him. He was dehydrated as he had cried himself out of tears. The men carried him out unable to get the story from him until one of the men picked up the bar to put it back when in front of his eyes four walls, 3 feet wide and to the ceiling came up trapping him. To the others he was just standing still unable to move. When another picked the bar up the first person is freed but the second is trapped. Luckily Agent Torres was there picking up a different artifact. Neutralizing the bar he called a regent in to pay for the single block as they took it back to the warehouse.