A sensation occurring when something seriously creeps you out. In many cases it will cause you to twitch and say "jibblies" involuntarily.
Strong Bad: You may notice I didn't do anything to the Poopsmith. I figure the guy shovels crap for a living so his tolerance for pain's gotta be through the roof. I was thinking about giving him a bath or something but, just the thought of that gave me the jibblies.