Well, here’s another week gone by, and I’m working on my post for the day kind of late. I didn’t home ’til a bit after midnight last night, and I was up early this morning to go help a local non-profit write curriculum material for math. After that, it was naptime, and I still hadn’t figured out what I was going to write about. On top of that, the XBox Live wasn’t working. Horrors!
So, I pulled up Netflix on my laptop, and I started to watch Hypothermia, a modest little film starring Michael Rooker (Henry: Portrait of a Serial Killer, The Walking Dead) about two ice-fishing families and a gill-man (see also this Hypothermia trailer and this fair-minded review of the film). After being interrupted by dinner, I finished watching the movie, and I had my topic for today.
Hit Dice: 3
Armor Class: 4 
Attacks: 2 claws (1d4), or fin slash (1d6 + infection)
Saving Throw: 14
Special: Feel vibrations, infection, surprise opponents on a 1-4
Move: 12/15 swimming
Challenge Level/XP: 5/240
The arctic gill-man is a monstrous hybrid of fish, reptile, and humanoid that dwells in some lakes of arctic regions. It breathes both water and air, and it can survive on land for a several hours without discomfort. This monster is territorial and intelligent, and it will seek to defend its territory against trespassers, especially those that fish the lake or hunt along its banks. When submerged, it can feel the vibrations caused by creatures in the water or moving on the lake ice. The arctic gill-man is quite stealthy, attacking by surprise against even alert opponents with a roll of 1–4 on a d6. In combat, it attacks with either its claws or else by slashing with one of the spiny fins growing along its forearms.
The gill-man’s fin slash carries a potent toxin. A living creature struck by a fin slash must make a saving throw. Failure means the injury caused by the fin slash cannot be healed by natural means. The failed save also means a fever sets in after 1d4+6 minutes. A feverish creature suffers a -1 penalty to both attack rolls and Armor Class. Magical healing is required to overcome the injury and infection. Furthermore, as long as a creature is affected by gill-man infection, the monster and its victim have a psychic link. The gill-man can infallibly track the infected victim and can communicate with the victim via telepathy as long as the gill-man can see the victim.