This crazy fuzz/delay/modulation/noise circuit is invented by Anchovie at the diystompboxes forum (original thread here) and is described as "extreme amounts of fuzz, delay, flanger-style sweeps, chorus, wobble and pitchbend effects. Veryboard layout here.
The loop switch toggles a 3.3M resistor between the input and the output for crazy feedback. Another good mod I did was to put a 4.7nF cap from the input to ground to keep the repeats from getting too harsh.
The loop in mode starts about 1:06. I play with the Chaos knob to pitch the feedback up or down.