Question: What is a word that can best describe YouTube bad content such as pranking videos, which negatively affect children? 

I thought about the word banal but it doesn't seem to fit. 

[Edit] As we know that children love to imitate actions they like, I'm implying the fact that this content, which get a lot of views by children, detrimentally affect children's personalities by persuading them to normalize inappropriate actions such as filming people on the street, generally invade other's privacies, bully or being offensive to others. Moreover, I'm comparing this type of content to the informative content on YouTube such educational videos

Answer: 
You could describe such content as being:

* **damaging**
* **harmful**
* **detrimental**
* **malignant**
* **poisoning**

For example -

> 
> Content on YouTube which glorifies jokes at the expense of others has a detrimental effect on the mental health of younger viewers.
> 
> 
>
You can use the catch-all phrase: 

> 
> "Content unsuitable for younger viewers"
> 
> 
>