Did your friends tell you these ones, too? If they do, there are a few possibilities:
1) A freaky coincidence. 2) A strangely similar sense of humor to both the Anti-Joke Chicken and the Lame Pun Coon. 3) They actually look at the memes. 4) All of the above.
A lot of these get 'opular' because they're put onto the meme. I only heard of these when you've shown me. So really, the meme are copying us.
Yep! Type in "gunpowder" on wiki. Or type in "elixer of life gunpowder" on google. I think it was during the Tang dynasty in the 8th century, but I'm doing this on my phone which means it would take too long for me to check.