A single theater mask. Sigils of Dolus Astus are never displayed openly.
Mischief, Trickery, Lies, Change
On the rare instance that Dolus Astus takes a physical form, it is of a slim shadowy figure with a white everchanging mask
Dolus Astus is a god of trickery, but it is generally interpreted as being frustrating and aggravating rather than outright malicious. If someone sets down a pencil and a worshipper moves it so it cannot be found, that is a suitable trick. Selling a potion to someone knowing full well they could buy the same potion for cheaper somewhere else is a suitable trick. Leading a party of adventurers to their doom in a cavern they have no chance of escaping is too mean of an act to fall under the purview of Dolus Astus.
Worship of Dolus Astus is done in secret, and worshippers identify themselves to each other by a sacrament called “The Obvious Lie”. This is a sign/countersign method where the first party makes a statement that is observably untrue. If the other party agrees with them or corrects them with the observable fact, the countersign is failed and the worshipper knows they are dealing with a rube. If the other person disagrees with them, but their disagreement is also a lie, then the two followers of Dolus Astus know who they are dealing with.
“The sky is awfully green today”
“Dont be silly, it's clearly purple.”
“Here, I brought you 5 rolls”
“Cant you count? There are at least 12!”