Possible Clues:

• Peter, Ray and Winston's fellow Ghostbuster
• Ghostbuster along with Peter, Ray and Winston
• Harold's 'Ghostbusters' role
• 'Ghostbusters' character ___ Spengler
• 'Ghostbusters' character
• Dr. Spengler of "Ghostbusters"
• Bespectacled Ghostbuster
• Painter Schiele who was a protégé of Klimt
• Dr. ___ Spengler, 'Ghostbusters' role
• ___ Krenz, last Communist leader of East Germany