Detroit (see above) has revealed a trident on the monument, although it was called the "big ugly fork" in the original news story. Woodyard has a new look at this Devil and others here.
Speaking of Detroit, the site of "Devil's Night" every October 30th, it is directly in the news in conjunction with Satan's followers coming to that city.
This is the same group that caused a stir when it said it wanted to erect a seven-foot tall statue of Satan near the Ten Commandments monument at the Oklahoma State Capitol. The proposed image (see above) of the statue suggested that the Temple wanted to depict Satan as a goat-headed Baphoment figure with a long beard, horns, and wings, with a pentagram design placed overhead. Two smiling children would be placed on both sides of the statue. Early reports of a Black Mass in Oklahoma also circulated. The plans for the Black Mass appear to be on a fast track.
However, the group’s leaders say they do not worship Satan. “We believe in a metaphorical, literary construct of Satan,” a Temple leader said. “He’s a symbol for rebellion, a symbol of human nature, the thirst for knowledge.”
"I'm going to have nightmares tonight," said one city worker who removed it around 3:15 p.m. PT.
As the Guardian reported in August 2014,
At the core of the Yazidis’ marginalization is their worship of a fallen angel, Melek Tawwus, or Peacock Angel, one of the seven angels that take primacy in their beliefs. Unlike the fall from grace of Satan, in the Judeo-Christian tradition, Melek Tawwus was forgiven and returned to heaven by God. The importance of Melek Tawwus to the Yazidis has given them an undeserved reputation for being devil-worshippers – a notoriety that, in the climate of extremism gripping Iraq, has turned life-threatening.
Representations, such as this one above, of the Kurdistan Yazidis’ Melek Tawwus or Melek Taus can have a trident-like appearance. It is a familiar image from The Exorcist movies, an overlap with the same region's Assyrian demon Pazuzu. To the Yazidis, Melek Taus is an angel; to ISIS, Melek Taus is Satan. It is the difference between life and death in modern day Iraq.
UPDATE: Conservative blogger Matt Drudge took an image from President Obama's 9/10 speech about confronting ISIL.
"We cannot erase every trace of evil from the world, and small groups of killers have the capacity to do great harm. That was the case before 9/11, and that remains true today." - President Obama, 9/10/2014
Drudge posted the 9/10 image to his blog on 9/11 with the caption "Photos Capture Obama's Head of Horns."
Needless to say, I have to point out it looks like a trident.
Of course, the real question is why would anyone wish to photoshop the real image - there are no drapes that low behind the president (see here) to make President Obama look like the Devil?
Synchromystic Symposium: The Meaning of Tridents."