Batman Beyond had a lot of really dark moments that I remember

• One episode has Batman battling a sentient AI program that is trying to upload itself into a person. Batman fights and ends up beating the program(who has taken control of the batsuit) when it mentally devolves into infancy all while crying out for it's mother before 'dying'

• Another episode has a news reporter who steals a belt that lets him become intangible and pass through objects/walls. At the end he cant control the intangibility anymore and slowly sinks into the ground while crying for help and then laughing manically where it's implied that he will sink until he reaches the center of the earth.

• The ending of another episode has a doctor whose wife was kidnapped by this gang while they force him to give them surgery. In the end it's revealed that the doctors wife was in cahoots with the bad guys the entire time. The leader of the gang comes in for surgery unaware that the doctor knows this and the last scene is him powering up a giant drill in the guys face.

Batman Beyond was a good show, but it scared me a lot as a kid.