One of my favorite obstacles I've ever placed in front of my players was a cat asking who they were. They couldn't progress until they answered due to the nature of the path they were traveling, but there was literally no way to get it wrong. The cat would accept any answer that wasn't outright bullshit and would never hurt them for lying. The duelist steps up and gives his noble affiliation, the commoner fast talker steps up and gives a not-quite-a-lie. They both repeat this process expecting to fight or talk their way through a problem that just doesn't exist, the others being too worried to do so until the npc they brought with them does the same. Eventually they all answer, with the secret heir to the throne not even giving away his title, then flounder until one of them just walks down the road. It was great watching them be so paranoid over a little cat.