Spectre 5 (July/Aug 68) is another all Neals Adams issue, but also the final one he works on.
The story seems a bit confusing, shielding the identities of two important characters, although by the end it all is clear, and makes perfect sense. A man with a white mask covering his face opens the tale, finding a glowing bullet.
Then the action shifts to follow a different man, giant-sized, with glowing eyes. The Spectre tries to fight this guy, who he calls Bright Eyes, but finds that when he tries, crowds go into a crazed panic, terrified of him.
The Spectre can tell he is being manipulated, and also is having his energies drained, but is not sure why this all is happening. When he tries to recharge by re-entering Jim Corrigan's body, he discovers that even Corrigan has turned against him, and wants to arrest him.
We can see that the masked man from the start of the tale is the one controlling Bright Eyes, and drawing the energy from the Spectre.
And once he has drawn enough power to destroy the white mask, we get to see that this is the Psycho-Pirate, last seen three years earlier in Showcase, when he fought Dr. Fate and Hourman. He was draining the Spectre's power, using the magic bullet of Azmodus, to remove the mask that Dr. Fate sealed over his face. Now he can use the emotion control the Medusa masks give him directly.
Psycho-Pirate orders the drifter he had empowered to kill Jim Corrigan, but at that point we, and the characters, find out that this is Gat Benson, the man who murdered Jim Corrigan in the first place, creating the Spectre. He had gone mad at the end of that story, and had spent his life wandering the streets. Benson breaks the magic globe that the Psycho-Pirate had used to boost his powers, which allows the Spectre to defeat the Psycho-Pirate, while Jim takes down Benson.
The Psycho-Pirate is not seen again until 1977, in the All-Star Comics revival.