I’m working on a campaign that has the player meet a creature pretending to be a sphynx and ask riddles of the players.
The trick is that that creature is both not that smart and thinks he’s very clever. They way past him is to praise him for being so smart that he agrees to let the adventurers go
What are some good ‘bad’ riddles to ask ?
I would say, use some classic riddles like the ones from The Hobbit, but then add one more line to the riddle that gives it away.
Also, recommend you have a look at this classic