Final answer:
Inversion is the contrapuntal device that presents the melody turned upside down (in mirror image).
Step-by-step explanation:
The contrapuntal device that presents the melody turned upside down (in mirror image) is called inversion.
In inversion, the original melody is played, but each interval is flipped upside down. For example, if the original melody has an ascending interval of a major third, in the inverted form, it would be a descending major third.
This contrapuntal technique creates a new musical line that mirrors the original melody, creating harmonic and melodic interest within a composition.