showing the cunning or ingenuity or wickedness typical of a devil; "devilish schemes"; "the cold calculation and diabolic art of some statesmen"; "the diabolical expression on his face"; "a mephistophelian glint in his eye"
mephistophelian. Dictionary.com. WordNet® 3.0. Princeton University. http://dictionary.reference.com/browse/mephistophelian (accessed: October 31, 2008).
Bob did not like Halloween. The pamphlets he gave the children explaining just how bad the corn syrup and refined sugar was for them, did not go over well. Those miniature mephistophelian miscreants let the air out of his tires, egged his house and performed other devilish Halloween tricks. What really bothered Bob was when their parents helped!