It's a spiral galaxy, like ours. It has multiple arms, wound fairly tightly, like ours, several of which split and have disconnected spurs, like ours. It even has that rectangular feature in the middle called a bar, caused by the odd gravitational interactions of several billion stars as they orbit near the galactic center. If you could travel a few hundred thousand light years straight out of our galaxy, you'd see something very much like UGC 12158.
...except for one small thing. Actually, a big thing: the Milky Way is among the biggest galaxies in the Universe, being 100,000 light years from side-to-side. But UGC 12158 has us cleanly whipped in the size department: it's 140,000 light years across! That's huge! Only a handful of spiral galaxies are bigger than this, making it one of the bruisers of the cosmos.
Image credit: ESA/Hubble & NASA