Big eyes
Alright, so we feel like this one is pretty easy to figure out, obviously, the man is wearing reflective glasses. To add to this, the thing he is looking at is his friend’s shirt which has a giant eyeball on it. When you combine the two using reflections, you get this effect.
We thought that we would not try to insult your intelligence and attempt to sell you some fake story about how he has the world’s craziest eyeballs. Some illusions are not as advanced as others, what can we say, we just like looking at them. Kind of like this guy liked looking at his shirt through the glass lenses.