Usually the place is littered with various artifacts from your prior entrances, but a while ago you took the time to clean up. Using the dumpster to get in this time was pretty satisfying, considering how hard it was to lug it over here before.
Here lies an artifact of one of your more recent attempts: a box of unused Joker-themed Halloween fireworks. The guy on the box looks nothing like the Joker. This pale imitation doesn't even have red lipstick. How are they Joker themed? Are the fireworks Joker-colored? No, you’ll be commiting no such boners as letting these priceless collectables go off on YOUR watch. You'll have to find out some other time, if you remember to come back for them.