Tweety gets one during the episode where the babies learn about their shadows for the first time. Having been previously accused of knocking over a sand-castle that Bugs, Lola and Sylvester were building (in fact, Tweety knocked over said sand-castle after tripping on a toy car buried in the sand), then having discovered that his shadow (which hasn't been explained to the babies yet) can appear MUCH bigger than himself, he proceeds to use it to scare the utter crap out of the other three.
In "The Brave Little Tweety", Tweety's friends give him a "hero suit" which they claim will make him braver. He starts going overboard with his heroic acts, so they take the suit away while he's napping. Tweety wakes up and sees the suit missing, and briefly freaks out - but literally half a second later, he becomes determined to help his friends anyway, suit or no suit.