It's the successor to the original Ninja Jamm app.
Designed by Coldcut's Matt Black, the Jamm Pro app improves upon its predecessor—Ninja Jamm—by introducing sampling, allowing users to record or upload their own sounds. A new "modular synth-like" approach to modulation, multitrack recording and resampling position Jamm Pro somewhere between a fully featured DAW, live performance tool or a sketchpad for musical ideas. But tools like a buffer shuffler, slice sequencer and macro control over multiple parameters offer opportunities for interesting sound design, too.
It's available to download for $9.99 on the App Store.
Learn about Jamm Pro's features in the demo video.