You could have the PCs be in service to an evil wizard or overlord, and just take any regular plot and give them the baddies' role. You could have multiple factions in a city, like noble houses, and give them some sort of goal to accomplish in that context. Think Game of Thrones or the drow in Menzoberranzan. You could have them doing something "good" but with a "the ends justify the means" mentality.

I like the "give them the baddies' role" idea. I'll think on that one, thanks

Ask your player what they mean by evil in this context. Do they mean evil as in oil barons extracting all the wealth they can by any means necessary, or does she want to skin babies to make purses?

pathfinder's begginers box. sorry. just being a fanboy ass.

I did ask and she just said she wants to cause trouble and be the bad guy. I know she's big into serial killers so more the skin babies side I'd guess.

Thing is, your typical clear-out-the-humanoid-tribe dungeon crawl could be considered pretty evil in its own right by modern standards. Just putting an emphasis on how much that old trope would actually involve disrupting lives and destroying families could be enough, depending on what she's going for.

I love doing this to my players. They go to loot a goblin body in a cave and find a baby rattle or something. They always get so upset. I could see taking that to it's max as a fun thing. An evil king wants a town cleared out so he can build a highway through it. It's the players job to clear the town

A heist job. The PCs are forced to kill, whether or not they want to. At a pivotal moment, an NPC from one PC's past shows up - or maybe just somebody who convincingly pretends to be one. They reveal information that makes it sound like the PC has been conspiring against the rest to split the hall with the NPC. Thing is, the NPC is lying. But is very convincing. In effect, you orchestrate a situation in which evil characters begin to infight. And because they're evil, it creates lots of opportunity for highjinks.

a town is planning a yuletide or similar celebration where they all pooled their resources to get an expensive icon. have them stake out the delivery and go into the town to steal the item, murdering anyone who resists

And they have to succeed a willpower save to keep the townspeople's singing from growing their hearts 3 sizes and making them bring back the gifts.

How about a "Suicide Squad" like run. The players can create all kinds of evil prisoners that get send to kill a thing that all the heros already failed to defeat. Now they can try do to what they are told to in exchange for their freedom or whatever or try to run away and force and not risk their own life's on the way. A lot of chances to play evil or even reconsider when the little orphan begs for help.

What kind of evil? Power fantasy of abuse and subjugation? Have them play vampires or demons. Awaken from their slumber in a small town and go about setting up a cult and securing their safety. Make thralls out of people. Add some sort of mechanic like "eating someone's soul gives you a stat boost" so mechanically they're rewarded for cruelty. Have NPCs beg for their life. Have some sell out their neighbors and loved ones for favor. Let the players kill them anyway. Maybe some heroes show up to fight them and free the people. Maybe it's just two hours of crushing limited resistance and making their temple.

Here's a podcast where they ran a one shot where they were evil characters who were all sentenced to death, but if they survived the dungeon, they would be spared. [Plot Points: Evil PCs Play Basic D&D](https://plotpoints.libsyn.com/evil-pcs-play-basic-dd-episode-127)

The king doesn't give a fig what's going on in the kingdom as long as he's got his ale and whores. He does not like when politics interfere with his revels and he can be rather brutal when it happens. The prince, an adult, has a pretty free hand but wants to avoid pissing off his overbearing father. The party is a small group of the princes drinking companions that the prince sometimes pays to solve his problems that threaten to rise to the level of annoying the king. The prince has lately been cavorting in some of the villages and claiming the right of prima nocta in his father's name. A group of villagers has decided to put an end to it. They've started ambushing patrols and maybe even made an attempt to capture the prince himself. The party needs to find and eliminate these trouble makers before his father finds out. This would be suitable for a low level party. If the players are higher level, switch it to the villagers having pooled their money and hired some adventurers of a suitable to take out the prince.