Haha this has to be referencing High School DxD. There is a special episode where they catch a guy like that who is doing the same thing.
"We thought he was just another pervert at first," said Nell, "but it turns out that it wasn't that simple. After breaching his base of operations, we discovered that he had used the stolen panties to make a magic circle, and that he was trying to conduct some sort of ritual."
Fantasy · Chiqui_Angeles
Yeah, it would probably have been better if they'd written "She's dangerously kawaii"
The sensei turns bright red and casts her eyes downwards. Dangerous, kawaii.
In Another World With My Smartphone.
Fantasy · FondSweet