Ray Stantz advised against gazing into it, citing that there are some things that man was never meant to see. Of course, after they climbed up the terrain to face the Power Flow Core, the boys did it anyway and screamed in terror upon doing so. After which, Peter Venkman quipped "I've gotta admit... I'm impressed!"
Near the center and the lower left corner of what's seen in the episode are what vaguely resemble the heads of snails or slugs, complete with eye stalks.