Glitchy and Scratchy meet Theramin and Mash it up
MetaToy 2 is based on an old R3 ensemble but rebuilt with new GUI, patches etc. It's capable of generating similar visuals to Metaphysical Function but unlike MF is not designed to just run and generate ambient sounds - you create your own sounds and visuals by scratching on the screen and/or using your midi keyboard (I tend to use both at once, mouse in one hand and midi keyboard with the other). The filter is also XY controllable.
This is a very expressive instrument and even very tiny subtle movements can radically shift the sound - and also just holding the mouse in one place can generate variations of pattern and sound for many patches. On the other hand wildly scratching around with the mouse can create sonic mayhem (watch the speakers though). So try everything - its made to be played with!
The sound can be a bit like MF but its mainly generated by pitchshifting and filtering and doesn't incorporate samples so it's probably more suited to whacked out space type sound effects and scratchy tape fx sounds.