Glowing dots for eyes on an otherwise black or obscured face.
It's common to see a hooded figure with their face completely obscured... except... except for their eyes. Their eyes glow with an unearthly light. They're often the only thing you can see of their face. There are two ways to go about this, the cute way and the creepy way. The cute way is where the creature itself isn't very (apparently) threatening, and this can kind of make the character reflect that while still fitting with the "darkness" theme of the character. Expect to see these on an Adorable Evil Minion. The creepy way is where the character is genuinely disturbing. Expect the color red, and an angry expression in these eyes. This is often the realm of Grim Reapers and the similar. The characters with these ones are often tall and gaunt. Compare Glowing Eyelights of Undeath, where these eyes are inside the eye sockets of a skull. See also Black Bead Eyes, By the Lights of Their Eyes.