Can beer REALLY go bad??

This is what I found on google:“Despite the fact that there are tons of weird beer flavors out there, it should be pretty clear if the flavor you're tasting is not intentional. Some common flavors that can indicate a bad beer are cooked cabbage, sewage, sulphur, or just an abnormally sour taste. Bad beer will not make you sick, it just tastes really bad. The only way beer could make you sick is if the equipment it is brewed in is dirty or used incorrectly. Beer typically lasts for six to nine months past the expiration date on its label. If the beer is refrigerated, it can last up to two years beyond the expiration date. It all depends on what your tolerance for those nasty flavors that come with bad beer is. Cans tend to last longer than bottles since they block out more light.”

Beer gets skunky when it's expired

It will taste flat or spoiled. It can cause a stomachache.