Infectious Personality is the first half of episode 8 of season 3 of My Life as a Teenage Robot.
After destroying a series of asteroids that threaten to destroy the Earth, Jenny returns home, bringing with her a dust that severely alters the characteristics of her close friends. Brad becomes afraid of everything (literally everything), Sheldon becomes an aggressive ape-like being that hates flowers (and becomes attracted to a lady wearing French attire), Tuck starts to constantly flatulate, to the point of becoming a balloon filled with his own gas, and Dr. Wakeman becomes very idiotic and goofy. It turns out the dust from the asteroid contained several bacteria-like creatures that used the bodies of Jenny's friends as a home because their old ones were destroyed. When Jenny brings back a meteorite for the microbe-like aliens to move back into, her friends return back to normal. But only one person left is infected...
- Brad is seen with eerily small, sharp teeth in his altered form.
- When Brad says "Woah, Pig Pen -- what's with the dust cloud?" he references the Peanuts character "Pig Pen" who is notorious for constantly trailing a cloud of dust and dirt wherever he goes.