Video prompt: A flock of migrating birds form intricate patterns across a twilight sky, shifting fluidly as one entity, silhouetted against the fading hues of sunset.
Defect: Deformation (when Object is involved in an act,  anything in this process that's weird. e.g. people walk into a wall. "Walk" is an act)
Explanation: As the swallow flaps its wings, its body undergoes unnatural shape changes, and at times the wings merge together, creating an unrealistic effect.