hyoid That is incorrect. The Sphenoid Bone is Bat-Shaped. The Hyoid bone is considered Horseshoe-shaped
stirrup
Crescent-shaped. (or, for you kidnap players, horseshoe-shaped.) :]
A horseshoe bend is a curve in a river that is shaped like the letter "U".
The horseshoe magnet is called that because it is shaped like a horseshoe.
Niagara Falls
Cirque
If you mean 'U-shaped' , it would probably be a horseshoe. It is sometimes belived to be lucky .
The "horseshoe crabs" get their nickname because their arc shaped exoskeleton. The nickname is not a proper name and therefore does not require capitalization.
sphenoid bone
kingman reef
Purple.