Gotham Doubles Down on Harley Quinn with Latest Comic Nod

WARNING: The following article contains spoilers for this week's episode of Gotham, "Ace Chemicals," which aired Thursday on Fox.

The Joker isn't the only character that Gotham has been teasing for nearly five years. His other half, Harley Quinn, was often promised to arrive on the series, but to no avail. At one point, it seemed like Barbara Kean was being groomed as a proto-Harley Quinn, but that didn't turn out to be the case. However, with the arrival of Jeremiah Valeska and his right-hand woman, Ecco, in Season 4, it sure looked like the series was finally making good on its promise.

It started slowly: Ecco, played by Francesca Root-Dodson, began wearing red-and-black costumes. She even briefly wore the classic court jester hat. While she was quiet in the beginning, she started behaving more erratically as time went on, the result of a self-inflicted gunshot to the head. Now, Ecco is utterly devoted to Jeremiah, and she helps him in whatever crazy scheme he cooks up.

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Then, in Season 5's "Penguin, Our Hero," Gotham made it official: Ecco really was the show's version of Harley Quinn, which was overtly confirmed when she called Selina Kyle "Puddin'." And now, with its latest episode, the series doubles down on Ecco's status as the true Harley Quinn.

In "Ace Chemicals," Ecco is once again at Jeremiah's side, a partner in crime as the would-be Joker embarks on his twisted mission to befriend Bruce Wayne. Part of Jeremiah's plan involves launching a chemical attack on Gotham City to prevent the government from intervening and rescuing the people stuck in No Man's Land. These chemicals are being manufactured at, you guessed it, Ace Chemicals.

Gotham: Ace Chemicals

Jim Gordon and Leslie Thompkins' investigation into the chemical attacks leads them to Ace Chemicals, where they are discovered by the Mad Hatter and Ecco. When Ecco makes herself known, she doesn't just barge on the scene -- no, she arrives skating by on roller skates.

While the scene may be brief, this is actually another direct nod to Harley Quinn. When the character received her own series as part of DC's New 52 relaunch in 2013, Harley had a new costume that was heavily inspired by the roller derby sport, given that she herself started playing. Since then, roller skates became associated with this modern version of the character.

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Having Ecco briefly zoom onto the screen wearing a pair of roller skates isn't just a nod to Harley Quinn, it's further proof that she truly is the series' version of the character.

However, that doesn't mean that, when the real Joker finally arrives to terrorize Gotham City, he won't be looking to manipulate a certain psychiatrist to become his latest right-hand woman.

Airing Thursdays at 8 p.m. ET/PT on Fox, Gotham stars Ben McKenzie as James Gordon, Donal Logue as Harvey Bullock, David Mazouz as Bruce Wayne, Robin Lord Taylor as Penguin, Camren Bicondova as Selina Kyle, Erin Richards as Barbara Kean, Sean Pertwee as Alfred Pennyworth and Francesca Root-Dodson as Ecco.

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