It is a supershell (a very large superbubble) within our galaxy that is spherical in shape and features jets of gas.
Discovered in 1970, this galactic object has subsequently been variously classified by researchers as a spiral arm of the Milky Way in 1972, a nearby tidally-stripped dwarf galaxy in 1975, and a high-velocity cloud in 1979.
[2] The name Snickers for the anticenter shell arose from the description in 1975 by Christian Simonson, a University of Maryland astronomer who believed it to be a small "peanut" of a galaxy just outside the Milky Way.
[4] The anticenter shell is approximately 55,000 light years (17 kpc) from the Sun.
[1] Its dimensions are difficult to determine by radio observation due to its location near the Zone of Avoidance, the regions of the sky obscured by interstellar dust along the galactic equator.