The sparkly slime-like substance is one of the most popular toys this festive season, as the popularity of slime-related videos on YouTube has soared.
Britain's main manufacturer of unicorn poo, H Grossman Ltd, say they are struggling to keep up with demand for the glittery slime.
Company director Martin Grossman said: "Unicorn poo is rare stuff, a bit like hens teeth.
"It's been amazing that we have sold nearly half a million pots of the stuff.
"Of course, we know where all the wild, free-range unicorns live, and in January I will be bringing even more pots of Unicorn Poo complete with little unicorns inside."
So far the company have sold almost a tonne of the 99p pots of sparkly poop.