Cover of Batman and Robin v.1 #22 (June 2011), cover art by Patrick Gleason, Mick Gray, and Alex Sinclair
Let me answer that question in the form of a riddle-me-this, shall I? When is 6 bigger than 8?
When it's upside-down.
If you're frightened by this unsettling image, you now know what the last 24 hours have been for me! Sweet dreams!
Comics Oughta Be Fun! does not guarantee that the mystery villain of this issue is Joker.