Back in high school when I was playing with the tennis team, there was one particular time when I was really thirsty but I had forgotten my water bottle. So, as any intelligent tennis player would do, I emptied the tennis balls out of my plastic tennis ball holder (much like this) and proceeded to fill it with water.
Off I went out to the courts, played my game and went to drink the water. But it had the oddest taste. It kind of stuck in the back of my throat. Burning and itching just a little. The uncomfortableness lasted for quite some time and then faded.
For whatever reason, the water I’m drinking right now out of my water bottle has that exact same taste. But there’s no sign of tennis balls anywhere nearby. I can’t explain it.