Joint And Several Liability
  
You and a neighbor build a sandbox for your local park. Unfortunately, you bought sand from a cut-rate website, which went out of business soon after you made your purchase. What you thought was sandbox sand turned out to be quicksand.
Now you're facing a lawsuit. One key determination that needs to be made early in the proceedings: are you and your neighbor jointly liable, severally liable, or jointly and severally liable?
Under that last one, both of you are independently on the hook for the entire sum of the liability. So if the parents of the kids lost in the quicksand sue for $10 million, each of you could end up having to pay $10 million.
If you were jointly liable, the defendants could win a judgment for $10 million against both of you, and you two would have to figure out how to split that $10 million liability.
If the liability were judged to fall into just the "severally" category, it would mean each of you would only be liable for your portion. You bought the sand, so the parents could sue you for that. But your neighbor did the installation, so any liability stemming from that aspect of the catastrophe...has nothing to do with you.