The Commodore!
I talked with OldDrewId and pointed him to this thread. We brainstormed a little more about the Lake Monster encounter. How's this sound:
The characters start seeing reports of missing boaters on the local news. Its written off as alcohol-related accidents at first, but the reports soon become too frequent even for that. Then a pier/boathouse gets torn up, looks like big chunks have been bitten off. The characters investigate and their boat gets bumped around a bit (keep the suspense going by not showing the monster). Imagine the scene of the bunch of em on a pontoon boat all staring at the big blip on the fish finder! Maybe someone falls in (fail your Balance check DC 15? In you go! Hope you put a rank into Swim!), somebody has to keep the boat in working order so they can get back to shore. Don't let them kill the beastie yet, there's more in store!
They make it back in, make plans, gather resources, heal up (if needed) and go back out on the lake. Lots of searching, but nothing turns up. Finally, they notice a section of the bank has been torn up - something big has moved through! They follow, eventually coming to another lake. Now they have to track down the beast here!
Here's the rub - the monster is a giant
snakehead fish that's been moving through the area. Maybe it got irradiated, maybe the chemicals in the area did it, maybe it's a government plot. You can use the fish's origin as a path into a longer running adventure. Whatever the cause, the players have to stop it. Do a little more research into breeding and feeding habits to add realism to the encounter.
One last idea: combine this scenario with my original suggestion of the giant catfish. The Commodore is a giant cat that lives in the first lake. A couple of different things may happen:
- The Commodore drives the snakehead away. The players encounter and kill the Commodore, thinking that ends the threat. Nope! Here it comes again in the new lake.
- Even better (and scarier!) - when they return to the lake after the first encounter, they find the carcass of the Commodore with huge chunks torn out of him. It's scary enough to find a huge catfish - but what the heck did that to him?!?! Bwaahaahaa!
After writing this, I like it even more. Their initial clue gathering could include talking to some old coot who fills them with stories of the Commodore (even giving them the name!) - planting the idea in their heads. Makes it even better when they find the Commodore's torn up corpse.
Again, I hope this helps. Let us all know how it turns out.