What is the single best one-liner you’ve ever heard a villain use? And if you don’t have any, imagine an encounter with the current BBEG of your campaign. What is the one thing they could they say to piss off your character?
I used Manshoon as an evil version of one of my players’ character (or the pc as a good version?). Manshoon had just allied himself to an ancient green dragon. My players were setting up an assault on the green dragon’s huge, city-sized lair.
Manshoon: “In the end, it will be I who will profit the most out of the… temporary allegiance.”
Manshoon clone PC: “She’s thousands of years old, has the eye of Vecna and an army of kobolds of thousands. Do you really think you can beat her?”
As the big bag evil half-fiend gnome had the the party at his mercy, all paralyzed by poison incense he was immune to, he decided he was going to kill one of the adventurers as an example and kill one of them every day until they told him what he wanted to know (and that the PCs actually did not know, he thought they were lying). Wondering aloud which to pick, he said "I guess I'll leave it to chance!" And then, amusing himself with his own unintentional pun, he grabbed the party priest of the god of luck, named Chance. "Yes, I will leave it to Chance to serve as an example!" and then ripped the top of his skull off, scooped out some of his brain and ate it as the others watched.
Chance was a beloved NPC, but it scene served its purpose. Before this the party was on the verge of fracturing, after this they were united in seeking revenge. (they of course escaped before another day had past and got away to gain allies and power).
My best villain one-liner was a written note in a treasure chest, combined with a simple trap: the floor of the room was a wall of force concealed by a simple illusion of a stone floor, over a 20' deep spiked pit. Opening the chest in the middle of the room, one simply finds a note therein, written by the necromancer who set the trap: "Dear intruders, reading this note triggers dispel magic. Signed, [the villain]. P.S., Toodles."
"And for your final wish, I will give you exactly what you wished for," the malevolent genie said, as he turned to face the party. "A lifelike statue of Sir Preston, made of solid gold!" The moment of dawning comprehension was forever frozen on the paladin's face as a flash of golden light transformed him, and all he carried, into purest gold.
While not D&D, this was said by a villainous mad scientist, who was planning on using a long range laser to carve his face into the moon. It was said to a PC that'd derided his plan, who had a chef background. The fact that the mad scientist was also a PC didn't detract from this hilarious moment in any way, shape, or form!