Back when I constantly needed a pen I used to use a Parker espirit telescopic fountain pen, since it was the best small fountain pen that cost little enough that I wouldn’t mind loosing, but it was still small enough and good enough for my tastes. More recently since I stopped needing an actual pen with any sort of frequency it just kept getting dry and I just decided to stop carrying one.
This days the only thing that I physically write with any sort of frequency are ttrpg character sheets and for those I just need a good pencil, so I moved to the wsd magnetic 2.0 mm lead holder. I just love it both as a great mechanical pencil and a fidget toy
Unbalanced centrifuge, IRL a small tabletop one like the image will just be a really expensive mistake, but the worst case scenario can indeed be lethal. Here is a larger one exploding https://www.youtube.com/watch?v=i8IOL5iLwG8