This is a single pen holder using Venom from the Spiderman movie and comic book series. I have to admit it is pretty awesome looking at your desk, I use it to hold my fine tip sharpie perfectly. This is a must have for any Spiderman fan.
Most pens fit just fine and it has a center of gravity low enough that it does not tip over. If you want to add more weigh I would suggest adding metal pellets or BBs into fill pattern while you pause the print.
Prints shown are right after printing and finished, acetone smoothed. There is no supports built into the model, I let my printing software add these in during slicing. Have fun removng supports!