WARNING: The following contains spoilers for the Harley Quinn Season 2, Episode 3, "Trapped," now streaming on DC Universe.

In the latest episode of DC Universe's hit show, Harley Quinn, Harley needs Firefly's flamethrower to melt her way into Mr. Freeze's lair and continue her war against the Injustice League. However, the flamethrower is currently in the Gotham Museum of Natural History which belongs to a villain named "Doctor Trap."

Trap pillaged every villain's lair during the chaos of Season 1's finale, stored all of it in the museum and set a series of deadly traps to guard his loot. Harley, Ivy and Kite Man enlist Catwoman's help to get inside and as they make their way through the museum, they discover a treasure trove of DC Comics and Batman Easter eggs.

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MISCELLANEOUS ITEMS

The first shot of Doctor Trap's museum seems to be its main hall and certainly contains the most densely packed collection of Easter eggs in the episode. The first display case contains Mad Hatter's signature hat which he uses to mind control anyone unlucky enough to be wearing one of his other pieces of headwear.

The next container is holding the armor of Azrael, the Angel of Vengeance. Azrael is one of Batman's strangest allies and has a complicated backstory involving pseudo-religious cults and a good deal of brainwashing. The first Azrael, Jean Paul-Valley, took over as Batman for a time after Bane broke Bruce Wayne's back and later assisted the Bat-family during the comic book version of No Man's Land.

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The third display case features five masks, four of which are easily identifiable. First up, Black Mask's headpiece is visible in the front row. Originally just a mask he wore for show, Roman Sionis eventually wore the mask full time after a fire permanently seared it to his face. The second mask belongs to Owlman, the evil version of Batman that resides on Earth-3 as a part of the Crime Syndicate of Amerika. The last piece of headwear belongs to the super-assassin Deadshot of Suicide Squad fame, although his signature red eye-scope is on the wrong side of the mask.

The fourth mask in the display case is never shown clearly and could belong to a number of different characters. It could belong to Nite-Owl from the Watchmen universe, or it could belong to the anti-Batman villain known as Wraith. Similarly, the "ears" on the mask could be meant to be feline in nature, which might mean it's Catman's cowl or the mask of the Red Lion, DC's version of the Marvel hero Black Panther.

Visible only in one shot, Riddler's cane is amidst the weapons on display in the museum, as are two of Penguin's attack umbrellas. The T-Rex most commonly seen decorating the bowels of the Batcave is also visible as is the giant coin that typically goes with it, though this version is a replica of Two-Faces doubles sided coin as opposed to the more standard penny.

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DOCTOR FATE'S HELMET, EGG HEAD'S EGG & AZRAEL'S SWORD

Further into the museum, the crew comes across a trio of strangely grouped displays. First up is a silver version of the Helm of Fate, the signature artifact of the Justice Society's Doctor Fate. Next to it is a giant Faberge egg in front of a picture of Egghead, a villain from Adam Wests' Batman television series. The final display appears to contain one of Azrael's Swords, though whether it is his Sword of Salvation or his Sword of Sin remains unclear.

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SCARECROW'S MASK, DEATHSTROKE'S SWORD & FIREFLY'S FLAMETHROWER

The crew also passes the signature mask of the late villain known as Scarecrow. The villain played a major role in Harley Quinn's first season but was killed in its finale episode by the Joker. Also visible is Deathstroke's sword, which is by far the hardest Easter egg to miss in the episode, as not only is the iconic blade clearly labeled, but Kite-Man also verbally name-checks seconds after Harley uses it to free him from a hanging net. Finally, the most expected reference in the episode is the flamethrower used by the pyro-maniacal villain Firefly. It can melt through anything, including Mr. Freeze's lair and the glass case meant to trap its would-be thieves.

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A COLLECTION OF MAYBES

The episode contains a number of potential easter eggs in addition to the many definite references. Unlike the others, it's not clear if these are meant to be anything specific or were simply items used to decorate the museum. For example, a dead body is sporting an outfit reminiscent of the classic blue Vault-Tech jumpsuit from the Fallout video game franchise.

Similarly, a spear inside one display case could be the Spear of Destiny, and multiple sets of bows and arrows could belong to Green Arrow or any of his archer allies. One room contains several boats and a couple of submarines, one of which looks like a fish and could belong to the penguin, but there is nothing to indicate that's the case.

DC Universe's Harley Quinn stars Kaley Cuoco, Lake Bell, Diedrich Bader, Alan Tudyk, Rahul Kohli, Christopher Meloni, Tony Hale, Ron Funches, Wanda Sykes, Natalie Morales, Giancarlo Esposito, Jason Alexander and J.B. Smoove. New episodes air on Fridays.

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