Analog saturation has long been used by audio engineers as a tool to manipulate audio, and is achieved by "pushing" analog circuits or analog tape beyond what are the normal operating levels. With the advent of digital recording, that practice has not been available. The Decapitator plug-in from Sound Toys steps in to fill the gap and can be used on drums, bass, vocals, guitars; to beef things up, thin things out, give them some edge, fry them up nice, add a bit of warmth, pull things out of the mix, or even create a signature sound.
What's more, Decapitator has the analog "feel" that you can hear as the subtle changes reacting to the track, following the dynamics of the instrument. This is not a static snapshot (no convolution here) but a changing responsive model of all those tubes and wires, and transistors that make up analog circuits. The modeled tone control lets you shape and contour, and a mix control lets you mix back in the dry signal without the need for routing and sub-mixes.
For the times when someone wants to really push the envelope to make sure their sounds are not nice, Sound Toys added a "Punish" button that kicks in another level of gain. This tool let's you drive the source material hard and it responds just like its analog counterpart - not the standard stomp-box distortion, but with those unique qualities that only come from driving high end studio gear.