The great Sphinx is the utter and complete symbol of ancient mystery. But while the real Sphinx might be merely inscrutable, the Sphinxes of the comics can be downright disagreeable.
There's the Sphinx of the Moon which made life quite difficult for some Earth astronauts. Both in this lovely cover by Gil Kane and the gorgeous wash by Murphy Anderson up top, the Sphinx is utter destruction for these brave men.
On Earth, the mighty robotic Sphinx named "Shagg" rose up and created no end of havoc thanks to the magic of Stan Lee and Jack Kirby.
For more on his escapades see this monstrous link.
And Sphinxes took part in the weirdest of wars too it seems.
The Incredible Hulk battled a Sphinx animated by alien Horusians and its partner named Colossus to boot. Of course the Hulk defeated these "Godspawn".
Here's a link with the "Hulkerific" details.
The Sphinx became a symbol of evil from across time when Rama-Tut used it.
Soon to become Kang the Conqueror, he used the Sphinx as a disguise for his time-traveling machinery. One wacky but intriguing theory suggests Shagg is this very time machine run amok.
And out of ancient Egypt, the name of the Sphinx was used by an evil sorcerer Anath-Na Mut who lived down through the ages thanks to the mysterious Ka Stone, and eventually came to battle Nova and the Fantastic Four.
Later a woman named Meryet Karim saps some of the Ka Stone energy and becomes another version of the Sphinx to battle the New Warriors.
So as you can see, the Sphinx in comics is a problematic beast at best.
Update: Here are another couple of Sphinxes-gone-wild I found. Sheesh!