This cover fake was based on the anecdote I'd heard about the origins of the Barbara Gordon Batgirl.  Seems that in 1966, when the Batman TV show was in full mania, the producers went to DC Comics to see if they had any other villainesses in the Batman lore, as the Julie Newmar Catwoman episodes had garnered a lot of positive feedback.  Carmine Infantino came up with a pile of sketches for villainesses, one of them being Poison Ivy and another Silver Fox.  Well the producers tossed ideas back and forth with Infantino and Julie Schwartz and at one point Poison Ivy was going to be on the show.  Then they changed their mind, deciding instead to use Silver Fox, but as a partner to Batman.  Then Silver Fox became Batgirl.  And DC, who had earlier done a Poison Ivy story in anticipation of the TV show, brought Batgirl out in 1967 in anticipation of the show.

So, doing my best Carmine Infantino impression (which isn't that good), I did a cover showing Poison Ivy taking revenge on "Silver Fox" for cheating her out of appearing on the Batman TV show.