So my group has been captured by some Kou-toa at the foothills of a mountain range (classic, I know) and instead of having them fight the little fish guys, I thought it would be fun for them to be “sacrificed” to try to bring their new deity to life. Thinking of them being pushed into a large pool in the middle of a cave room and have it drain out from under them and……

That’s where I’m stuck. I don’t know how i would run the mechanics of them going down a slide (avoiding rocks jutting out of the water, potentially running into the walls on the side, maybe a big drop in there somewhere) and not sure where they would end up. I don’t want it to be a true life threatening trap, just something to make it a little lighthearted and fun (i got a couple of newbies in the group). You guys got any ideas on the mechanics of an underground waterslide? And where it might spit them out?

Thanks!

A skill challenge would work, they are a mechanic from 4e and this is the basic run down :

1.  Describe an obstacle.
2. Players suggest a way to bypass it with a skill or tool and roll.
3. set a dc based on how much sense it makes for that to work. So a good answer has 1 dc an ok dc has another 
4. If they succeed they get a point and if they fail to lose a point.
5. Repeat until they hit a certain threshold of successes or failures. 
6. consequences or rewards based on success or failure 

My first thought was along the lines of the "super fun happy slide" in that Simpsons Treehouse of Horror - have some sort of trigger that if it gets touched, like maybe a certain rock getting moved, turns a steep rocky path into a slope that's too slippery to stand on. Maybe start with your characters in a cell or something looking for a trapdoor or hidden exit & they stumble across the trigger then the floor gives way under them. 

Great idea! I’ve looked up a couple of websites and think that could really work! Thanks Solar!