Describe dark/evil eyes

I have never seen any (that I know of). What are people talking about specifically when they say this? Is this the same thing as an unflickering stare?

Dunno, I can make most people be scared.

eyes Muahahah

Mostly it’s a squint, I think, with…just a little bit of an arched brow. At least my personal flavor of it is.

People always tell me I look mad. It seems to be the eyebrows more than the eyes themselves.
If I keep a straight face but tilt my head down a little I look mad, if I arch my eyebrows the illusion is broken.