The child has been exposed to a subliminal advertisement. It is a form of advertisement which aims to create an unconscious influence over the target audience by creating subliminal stimuli which appeal to an individual's current needs or goals.
In this case, the advertisement was probably aiming to create a reluctance in the viewers over the use of toilets. They tried to achieve this by depicting the toilet as a monster who is the user. This effectively caused the child to be fearful of the toilet and reluctant to use it.