Here's how I see the basilisk:
Say your walking in the jungle and a big snake pops up. What do you do? You freeze. You're frightened. You’re a prey animal. You’re like a rabbit, and you’ve seen something that's going to eat you. You freeze, and you’re paralyzed. You’re turned to stone, which is what you do when you see a basilisk or a gorgon.
The reason you do that is because you’re using the predator detector system to protect yourself. Your heart rate goes way up, and you get ready to move. Things that upset us rely on that system.
The intelligence in the eyes of that monster practically radiate outward. It's extremely effective at making the viewer feel a sense of menace that only comes from an animal that is intelligent enough to be cruel, vicious, and sadistic. And the casual posture of Riddle in this one conveys his position of authority over the gigantic bred-for-glory killing machine behind him. It's very obvious who is the bigger threat here out of the two of them just by Riddle's expression and body language alone.
It's pretty scary. Riddle's body language commands respect and attention, but also shows his complete lack of fear in that position. If The Philosopher's Stone is the origin story, then Chamber of Secrets is a horror story.