Wear an aqua blue top. To really get your costume looking right, try to get an aqua-blue hooded sweatshirt, t-shirt, or tank-top to turn into your Rainbow Dash costume. You don't really need to do anything to the shirt to make a costume out of it, just make sure it's the right color.
Kraft Vegemite Yeast Spread is a dark brown Australian food paste made from leftover brewers' yeast extract with various vegetable and spice additives developed by Cyril P. Callister in Melbourne, Victoria, in 1922.
In reality, the makers of Velveeta weren't looking for a way to melt cheese down--they were looking for a way to put cheese back together. And, though it's owned by, and most heavily associated with, Kraft now, Velveeta was not one of James L. Kraft's cheese creations. The Frankenstein behind the cheese creation was one Emil Frey, a Swiss cheesemaker who moved from Switzerland to upstate New York, where he worked in cheese factories in the late 1880s.