The Spider Nebula (IC 417 / SH2-234) and the Fly Nebula (NGC 1931 / SH2-237) are two neighboring star-forming regions in the constellation Auriga. 

Spider Nebula is an HII region and star-forming nebula located about 10,000 light-years away. It contains young, massive stars that ionize the surrounding gas, creating a glowing effect.  It is often called the Spider Nebule due to its filamentary structure, which resembles spider legs stretching through space.  

NGC 1931 / SH2-237 is often referred to as the "fly" to IC 417’s "spider".   The Fly Nebula is a compact emission and reflection nebula that also hosts a small open star cluster. It is sometimes called a miniature Orion Nebula due to its structure, combining an HII region with dust reflecting starlight.  The nebula is about 7,000 light-years away and spans roughly 3 light-years across.  

Together, these nebulae form a visually striking pair and are active sites of stellar birth and evolution.