This unremarkable powder rather resembles chalk dust or powdered graphite—unless it is stared at. It then becomes evident that it is something entirely different, for the dust changes color and form under scrutiny. 

A pinch of dust of illusion allows the creature dusted to appear as any other creature of similar shape, with a size variance of 50% (plus or minus) from the actual size of the affected creature. (An unwilling recipient is allowed a saving throw versus spell to escape the effect.) 

Thus, a halfling could appear as a human of small stature, a human as an ogre, a pegasus as a mule, etc. 

The individual who sprinkles the pinch of magical dust must envision the illusion desired as the powder is shaken over the subject creature. 

The illusionary power lasts for 7-12 hours unless otherwise dispelled. 

A typical pouch of this dust will contain 11-20 pinches.