Can you make yourself faint by looking at something that makes scared?

Yes. Some people may experience vasovagal syncope, aka the "fainting reflex". It occurs in response to emotional stimulus (like fear, panic), pain, stress, dehydration, low blood sugar. The heart slows down, which lowers blood pressure, depriving brain temporarily of oxygen. Fainting lasts until blood flows properly throughout the body. While rare, some people have fainted upon seeing something frightening.