This is spiral galaxy Arp 188, the Tadpole Galaxy. The cosmic tadpole is a 420 million light-years distant toward the northern constellation Draco. Its eye-catching tail is about 280,000 light-years long and features massive, bright blue star clusters. One story goes that a more compact intruder galaxy crossed in front of Arp 188 and was slung around behind the Tadpole by their gravitational attraction. During the close encounter, tidal forces drew out the spiral galaxy’s stars, gas, and dust forming the spectacular tail. Following its terrestrial namesake, the Tadpole Galaxy will likely lose its tail as it grows older, the tail’s star clusters forming smaller satellites of the large spiral galaxy.
You can also see many other distant galaxies in background, two toward top-right and one toward left-center of the image.
I took this image over 13 hours (26 luminance images of 20 minutes each and 9 images of 10 minutes each for 3 colors).