Notice the sleek, greyhound like appearance of the body. Ancient Egypt Magazine gives a close-up of this image of Set in the August/September 2009 issue:

Author Ken Moss says it is "Seth from an Eighteenth Dynasty relief in the Open Air Museum at Karnak."
Hmm, The KMT author declares it is from Senwosret I's chapel, which is from the Twelfth Dynasty. ???
But Ken Moss shows this glyph in larger context, with a Horus falcon above it:

Putting this piece in further context is Eugene Cruz-Uribe, who wrote for Journal of the American Research Center in Egypt, "Seth, God of Power and Might", issue 45: The hieroglyphs "may read '[year]s of Horus and Seth, living.'" There's a similar fragment in the Open Air Museum, also given a line drawing by Cruz-Uribe: "It shows a partial figure of a king with a portion of an inscription behind. It reads '[...H]orus and Seth in the kingship of the two lan[ds...].'"