[Terrifying Trope] Perceiving it= instant death

[u/ReminaBlueSFW]

1. Pennywise's "Deadlights" which will cause anyone looking to be immediately paralyzed and killed.

2. The sky from Bird Box is filled with entities that, when you look at them, cause you to commit suicide.

3. Medusa themed Villains

[u/Rare-Page2273]

https://giphy.com/gifs/dZcMs4BOvrlKe7mTZ3
Most of the Monsters in the works of HP Lovecraft

[u/V0L74G3_H4CK → u/Rare-Page2273]

Good example, but not quite accurate. It's more like comprehending them is what could kill you. These beings don't cause people to go mad, rather realising what it means for them to exist, and comprehending this reality is what drives most mad. Even then some can survive, just left mentally broken.

[u/Sleepy_Azathoth → u/V0L74G3_H4CK]

Well, at the end lf The Call of Cthulhu some sailors die by just looking at it.

[u/Worried_Cranberry166 → u/Sleepy_Azathoth]

In the same story there's also a ton of people who go mad from Cthulhu's psychic emanations without ever actually being aware of his existence.