I'd put all of anime if possible or weird internet shows like cocomelon.
TV shows haven't been as damaging as that since alot of it needed to be tested and screened before airing and really weird shows never became super popular.
Though if I had to pick only one tv show, it would be Invader Zim. It did to adolescents then what rick and morty did to man children, making them insufferable. The weirdest kid was always into it, sometimes quoting the show thinking it was cool and made the other kids hate them. I don't think any other show was as devstating without help from the internet or fucked up community as Invader Zim to a child's ability to socially interact and healthy interests from being introduced to that show.