He could do this with a well-timed perp walk of some Grrrrrreeeedy Oil Speculators that would have the effect of collapsing the futures market.
No, that would not do it! Greeeeedy Oil Speculators have lawyers who would get the targetted individual off the hook. Also, oil is traded on markets overseas. If the US futures markets become unavailable to oil speculators then they would switch to the Hong Kong exchange...or some other exchange. One other thing to remember...eventually (after driving season) oil and gas prices begin to recede because oil speculators react to the reduced demand and bid those prices down. 0bama would need those speculators to be in place and active when that time comes...if speculators are pi#&ed off at him they might not be willing to reduce those prices in September/October when he needs them reduced.
The truth of the matter is that much of the runup in oil prices is due to the Fed and ECB printing so darn much money. At this point, all that money printing cannot be undone.