You’re bleeding somewhere and it’s reaching your stomach. The partially digested blood comes up looking like coffee grounds. If you have a bowel movement that is black and sticky like tar, see a doctor. You may be bleeding internally in your lower gi track.
If you ever almost drown to the point of throwing up water or passing out, even if you feel 100% fine, get to a hospital. Your lungs can unwittingly self-fill up with fluid over the next few hours.
When having a heart attack, you don’t swallow asprin, you chew it. Then swallow.
If you’re ever somewhere really high (e.g. hiking) and you hear crunchy/crinkling noises in the air and/or feel static electricity (like your hair standing up) , get out of there immediately, lightning is on it’s way.
If you’re at the beach and the ocean suddenly recedes, get to high ground. ASAP
Rohypnol, the date rape drug, has a salty taste to it.