Based on a combination of novel mapping techniques and carefully designed sound engines, I present an augmented hybrid piano specifically designed for improvisation. The mapping technique, originally developed for other control interfaces but here adapted to the piano keyboard, is based on a dynamic vectorization of control parameters, allowing both wild sonic exploration and minute intimate expression. The original piano sound is used as the sole sound source, subjected to processing techniques such as virtual resonance strings, dynamic buffer shuffling, and acoustic and virtual feedback. Thanks to speaker and microphone placement, the acoustic and processed sounds interact in both directions and blend into one new instrument. This also allows for unorthodox playing (knocking, plucking, shouting). Processing parameters are controlled from the keyboard playing alone, allowing intuitive control of complex processing by ear, integrating expressive musical playing with sonic exploration. The instrument is not random, but somewhat unpredictable. This feeds into the improvisation, defining a particular idiomatics of the instruments. Hence, the instrument itself is an essential part of the musical work. Performances include concerts in UK, Japan, Singapore, Australia and Sweden, in solos and ensembles, performed by several pianists. Variations of this hybrid instrument for digital keyboards are also presented.