HELP! My ATV back shock is messed up
 

So I just took my ATV (the guy I bought it from said its a 125cc 2008 gio atv) for a short ride, and when I got back I noticed some black liquid leaking out from where the black shock is. When I checked it out, the shock was no longer connected to the axle thing, and a ton of this black stuff leaked out. What is the problem, how do I fix it, and what do I need to fix it? I know nothing about this stuff...
https://i.ibb.co/zGttXP2/atvv.png
https://i.ibb.co/yY9z7hy/atvvv.png
https://i.ibb.co/6YLsMVq/atvvvvv.png

The shock consists of the spring and the piston, and your piston is a type filled with hydraulic oil. The seals on the piston are shot and leaking.
Your options are:
1. Take it all apart and replace the seals in the piston, then fill it back up.
2. Measure the one you have and replace it entirely.
3. It is hard to tell from the photo, but it looks like the bracket the shock bolts into snapped off, and you or a welder will need to fabricate a new bracket and weld it on.

Option 2 is the best IMO since hunting down seals for it might be a lot of trouble.
If it's totally disconnected and you can find seals, it will be a lot cheaper and you don't have to deal with compressing it for removal, but I still think replacement is a better decision. You can find a lot of variety on Ebay and Amazon starting from around $25, and it will be superior to something made in China X years ago. You will have air and hydraulic to choose from, research the differences and decide for yourself.

My shocks are stock Chinese Pentora, but they're still very nice for what they are. Far superior to what is on my X-Motos dirt bike, granted it has a BMW fork and suspension. When it comes to pulling ATV and dirtbike shocks, they can spear out at you if not compressed with the proper device, but I have done it crudely in the past and it's thrusting away was loud and scary but, posed no obvious danger on mine.