Akanbe is a Japanese facial gesture. It consists of a character pulling down their lower eyelid to expose the red underside. It is considered an immature taunting gesture. It is often accompanied by the characters blowing a raspberry.
References:
Mon œil:
In France, the gesture of pulling down one's lower eyelid and saying mon œil, or "my eye", is an expression of disdainful, dismissive disbelief.