Michał Krzysztof Łapaj (born 3 March 1982) is a Polish musician, composer, producer, instrumentalist, and sound designer. He is best known for his longstanding performances in the progressive metal band Riverside, of which he has been a member since 2003. He has also appeared on albums by projects such as Leash Eye, Behemoth, Antigama, Lunatic Soul, and Tangerine Dream.