First off, I LOVE your sketching style. It reminds me of a graphic novel series from my former publisher Alterna Comics (Lil' Hero Artists was first published there for a good while), called Mr. Scootles. It's next to impossible to find a good quality copy of it these days, but your style here very much matches the one in that comic. I sometimes do the same thing when I'm drawing with a standard ol' Bic pen. The fixed width allows for easy crosshatching and such. And I love how The Pirahna almost feels like the "North Star" in the picture (Hey, it IS Christmas, after all! 😉)

And Merry Christmas to you, too! 🎄🧑🏾‍🎄❄️🌌