I'll start
Final form hexxus
I'm not sure if he could be called a villan in batman beyond but this episode was unsettling.
Judge Doom after his reveal....
Charnobog...
Pretty much anything with red or yellow evil eyes scared me as a kid.
>>82409805
He just had to scratch you and you'd go full Chernobyl
>>82409823
Most Batman Beyond episodes were unsettling
>>82409990
Yeah this guy just wanted a high kill count period.
EGB in general was scary to me as a kid, but Grundel was especially so.
The bogeyman from the original ghostbusters
> Dat voice
> Lived in surreal extradimensional space
> The 'clop clop clop' of his hooves as he stalked you through his dimension
Not a villain, but this cat was fucking creepy as hell to me as a 4-year-old kid. I hated it and would cry when it came on during my favourite preschool TV show.
https://www.youtube.com/watch?v=QVotVFjjHxM
>>82410228
He was only doing what he existed to do though, being a virus n shit.
Besides Frank was a fat piece of shit anyway. Survival of the fittest.