APE

Or do you mean Ape?

APEs are AVS Plugin Effects for Advanced Visualization Studio computer software. They are usually coded in C++ and can be made with an SDK that can be downloaded from the Winamp website. Some APEs are distributed with AVS, e.g. Firewurx, Texer II, Color Map and Convolution Filter.

APE is also the file extension used by the Monkey's Audio Lossless Audio Compression Format.