Sometimes the best visual effects are the ones no-one will ever notice. When Oenomaus took a knife to the eye, the gruesome result was originally realized as a physical prosthetic. While the match of skin tone, texture and realism was great, the decision was made after shooting that the wound should be more of a cavity than a swollen protrusion. Wanting to avoid a costly and time-consuming 3D matchmove and render, we elected to try a 2D solution based on a classic optical illusion; that convex objects when rotated 180 degrees read as concave. This approach paid off as it allowed us to use the shot footage itself rather than a complex skin shader with dynamic lighting. There was still a huge amount of meticulous hand tracking, warping and blending that went into each setup, but the final result held up even in extreme closeup.