The following commentary comes from an independent investor or market observer as part of TheStreet's guest contributor program, which is separate from the company's news coverage.NEW YORK ( TheStreet) -- The worst investment in the world, the United States Natural Gas fund ( UNG) has again revealed how cruddy it is by announcing a four-for-one reverse split as of Feb. 22. Anyone who still holds this turkey expecting it to even approximate the price movement of natural gas should be convinced by this last move to get out of this horrible fund. Futures-based ETFs start with a grave disadvantage in the ETF world: instead of using various groupings of stocks to replicate the movement in a sector, they must use futures contracts and over-the-counter swaps to try and capture the price movement of an underlying commodity. While there may be a terrific appetite for investors afraid or unwilling to engage in the futures market to bet on prices of natural gas or crude oil, there is really no good way to represent these commodities like stocks. Most of these ETFs are programmed to fail.