General Approaches:
* Raised eyebrows: This is a classic facial expression of disbelief or surprise. It could be depicted as a simple line drawing or even a more detailed illustration.
* Open mouth/gape: This conveys shock and astonishment. It could be shown as a simple silhouette or a more elaborate illustration of a wide-open mouth.
* Question mark: This symbol directly represents questioning and doubt. It could be enlarged or stylized to emphasize disbelief.
* Exaggerated facial expressions: Think of cartoon-like expressions with wide eyes, a dropped jaw, or a furrowed brow. These can visually communicate the feeling of being taken aback.
Specific Examples:
* "Nope" meme: This image of a black man shaking his head in disbelief has become synonymous with incredulity.
* "You're telling me" meme: This image often features a person with a surprised expression, perhaps accompanied by text like "You're telling me!" or "No way!"
* "Are you kidding me?" meme: This often uses images with a shocked or confused expression, sometimes paired with the actual phrase "Are you kidding me?"
Ultimately, the best symbol for incredulousness will depend on the context and the specific message you want to convey.