A VST effects plugin.
Transformant provides a multichannel formant filter effect that is tailored to provide gritty, honking, nasal grunts rather than pristine angelic choirs. The sounds can be shaped across the stereo field with separate oscillators and vowel controls while the sound can be routed through a distortion chain to really accent the odd harmonics.
Transformant works best on spectrally rich input (such as sawtooth bass or drums), but with subtle adjustment of the controls you will never know what kind of otherworldly howls you can extract from the most mundane of sound sources.
The archive contains VST2.4 and VST3.0 plugins for both macOS (10.10/Yosemite and higher) and Windows 10. Additionally macOS users can also use Transformant as an Audio Unit, Linux packages are currently not provided, though you can build from source. Installation instructions are provided inside the archive's README file.