O'Neil, Ernie Chan and Garcia-Lopez send the Creeper after the Joker in issue 4 (Sept/Oct 75). The Creeper had last been seen a few months earlier in Detective Comics, in the conclusion of the Bat-Murderer storyline.
Benny Khiss and Marvin Fargo have small roles at the top of this story. They are now working as security guards in a museum, which gets robbed of a valuable gold Cellini clown mask. They are sure the Joker was the thief, but the curator of the museum blames the crime on the Creeper. Jack Ryder is doing the interview in which this charge gets laid, and knows full well he did not steal the mask, so he is inclined to believe the two guards.
Ryder changes into the Creeper and goes after the Joker. He finds him pretty fast, but winds up losing his fight with the villain. The Creeper gets knocked out, and neither notice that the device he uses to change into his other identity falls into the Joker's breast pocket.
The Joker decides to kidnap the artist who draws a strip clearly meant to be Peanuts, with Charlie Brown, and collect a ransom for him. When the Creeper comes to he has lost his memory, so the Joker enlists his aid and sends him out to perform the actual kidnapping.
In the best scene in the tale, the Joker gets the artist to draw him beating up the Charlie Brown character, and the artist enjoys this so much he doesn't even try to escape. The Joker sets up the Creeper to be killed with a bomb, and is so pleased with how his plans are turning out that he hugs himself.
In a very nicely done layout we see that the Joker has unwittingly depressed the device while hugging himself, turning the Creeper back into Jack Ryder. This restores his memory, and he ditches the bomb before it goes off.
Jack returns to fight the Joker, and the device falls out of the Joker's pocket, allowing Ryder to turn back into the Creeper and take the villain down.
It's a fun story, though not perhaps the Creeper's most impressive outing. The finale bills the Creeper's upcoming appearance in 1st Issue Special.