1. Alien
Most Sci-Fi films teach us that aliens from other planets tend to love sticking things into us. It can be probes, mind controlling bugs or they simply just want to wipe us out. Ridley Scotts horror Sci-Fi set the bar to all new high with facehuggers grabbing your face planting an egg inside you and few hours later a chest bursting xenomorph baby ruins your evening. The 1979 Alien chestbursting scene with Kane would be my number one choice. Why? It is brilliantly gory, Kanes scream just makes you want to cover your ears and the final beautiful blood splatter shock makes you shield your eyes and look away. That scene just came out of nowhere and still catches the first time viewers off guard. Everyone in the scene is chowing down on space food, smoking their futuristic E-Lites then suddenly Kane begins to cough and cough more violently. All of a sudden this nice evening of space food is ruin with Kane screaming in pain with everyone holding him down. Then unexpectedly blood is splattered everywhere. I really doubt space washing up liquid will get those stains out.