The intro?
I think its a pitchshift pedal or a harmonizer set an octave (or thereabouts) lower with some delay. The guitarist Russel uses an insane amount of effects so its probably just some combination of pedals. Could even be a Electro-Harmonix POG Polyphonic Octave Generator.

I think I have the little casio keyboard that a few of the samples are from. Brings back memories.