If you wanted to be a sign of theological danger, it would obviously be an eye inside the yellow triangle.* In this fashion, Bill Cipher character from Gravity

If you wanted to be a sign of theological danger, it would obviously be an eye inside the yellow triangle.* In this fashion, Bill Cipher character from Gravity Falls is the walking sign of theological danger and also that danger incarnate. * - if ancient Greek would be inventing that sign, they'll surely pick Zeus' ligtning bolt inside the yellow triangle - e.g. the one we use for electricity