Bubble counter fluid:
Having blundered the CO2 earlier, I was left with an oil slick of bubble counter fluid. While it's not supposed to be harmful, it is unsightly. So I wanted to at least get out what I could.
I decided to try to get some of it out by using the python as a skimmer of sorts. So I skimmed off the top, added water, skimmed it again, on and on.
During this time, one of my guppies (my original mama) swam into the python. She was only about 6" into the hose, but nothing I did could get her to go back. She would just swim further and further down the hose. So I decided, fine. I'll see if I can push her back out by reversing the water.
Next thing I knew, the water exploded along with my mama guppy who was now decapitated.
At least it was fast so she didn't suffer much.