Evil... until recently, my most heinous acts were commit by by CN rogue.
It started by impersonating a paladin of the god of vengeance (homebrew) in order to gain said paladin's trust and sell her stuff while she does not notice me selling drugs to the villagers. The plan quickly went downhill after she nat 20 a sense motive check and started pelting me with arrows. This led to a chase scene and her having custody of my character for his rehabilitation. Fast forward a few weeks of this chafing, and I was rather annoyed (especially at the DM for allowing this) so I hatched the following convoluted scheme. The party needed me as I was the only one that had a fast means of transport (an airship, it was one of those games) and we were flying over a desert, when the ship was attacked by cannonfire. The paladin was not in the action on account of not feeling well, courtesy of a drugged breakfast, so the only person that had a good sense motive was down and unable to realize that my plan of "descend to the ground via rope ladder and do battle while I land the ship safely" was a load of bunk. After ditching the party in the desert, including the sorcerer, an young and terrified elven child, I sold the paladin, used the proceeds to hire a band of mercenaries and attack a small feudal lord who had a grudge against me due to an altercation with his daughter.
Since then I have been banned from playing rogue or anything with a positive charisma bonus.
The more recent evil was my wizard. We found a major artifact, a Neogi starship of all things, and my wizard had as his goal the colonization of space (Had already built a space station by lax interpretations of certain rules), and after clearing it out needed to figure out how it worked. My character immediately guessed "The dying screams of newborn babies" (The answer was sentient life) and transmutes one of the bodies into a live human infant (because polymorph any object can do some freakish stuff) and plugs it into the machine. Every time the baby died, I repeated the process. The DM declared that I have perverted one of the multiverse's most sacred acts, the creation of a soul, in a revolting way and shifts my alignment to vile (Because evil was not enough) and gave me the abberation type, saying my mind works in such twisted ways that I had voided my humanity. He said it also helped that I had chain baleful polymorphed a load of people into kittens which I made into a milkshake for the party's hellfire warlock. It was one of those nights. Now, with the game scheduled to continue next semester into the epic, my wizard is set to become Cthulhu, as an abberation horror from beyond the stars (He can turn into a gibbering orb by breaking shapechange), landing on worlds and doing overall terrible things to people. I think the DM might cry.