I didn't have a huge amount of time to play (I hate deadlines! I'm supposed to be retired) but I had a quick go and got something similar by using the following effects:
First, I used Effects/Time and Pitch/Pitch Shifter to lower the voice. I started using a preset called "The Dark Lord" but it was too much for the voice I was using and I got better results at about -9 Semitones. This will vary depending on the voice you're starting with.
Second, I added Effects/Chorus/Flanger and started with the Thick Chorus preset. I found I could get closer to your sample if I reduced the Intensity slider to around 75% but again you'll need to play with setting for the voice you're starting with.
Finally, I added Effects/Distortion to the effects rack and used the "Swamp Thing" preset. I didn't have time to play but tweaking some adjustments might get it even closer to what you're trying to do.
Sorry I'm a bit vague but I hope this at least points you in the right direction.
I'm off to finish blowing up Baghdad in a video. Don't ask. It's a long story!