When I spotted this Spectacled Caiman, it was facing to the wrong side. Instead of looking fiercely in my camera, it turned its whole body so I only got this side 'effect'. Luckily it did not swim away or disappeared under. That is usually their normal behavior when they are a bit fed up with my presence.
This Spectacled Caiman had also a perfect camouflage because when they lay still like this near the river edge, 8 out of 10 times you will successfully miss them.