Picollus is a demon of the Dictionnaire Infernal who would appear to important people near their time of passing. The head of a dead man and burning tallow were to be presented in his honor. If he was not appeased, he would return a second and third time. If he returned a third time, only spilled blood would satisfy him.
The name seems to be drawn from an Old Prussian underworld deity variously known as Peckols or Patollo, who is often divided in Christian sources such as The Sudovian Book into two separate deities. This deity had believers well into the 17th century in what is now northern Poland.