Very Moog. This was around the time when the synthesiser was a real novelty. And synths can make pretty creepy sounds. Think of the PBS jingle from a couple of years later. Think of the Viacom Flying V From Hell closing logo. Seriously folks…it's all in the synth. If that had been a little girl with, say, an orchestral backup or someone playing acoustic guitar, the commercial would have had less than a fraction of the creep value.