A cartoon gag where a light bulb appears over a character's head, illustrating their sudden burst of inspiration. Occasionally, a physical light source is used instead.
The visual bulb is usually accompanied by a musical chime of some sort. It has become so synonymous with the trope, that the chime is sometimes rung without the visual. Examples include:
- Each idea Big Bird gets for how to remove the snow in Sesame Street Episode 0602 is marked with a chime.
- Oscar the Grouch getting an idea for a disguise to hide from Mr. Hooper and his brother in Episode 1545.
- In a 1974 story insert, The Monster's Three Wishes, Cookie Monster gets an idea. His chiming sound effect startles The Genie.