How would you stat it out?
Dunno but you need to show us a picture of one.
Sounds like a large aquatic with plant traits creature. I'm assuming it's an underwater beastie?
With abilities like
*poison touch/skin - harms those using natural/unarmed attacks
* an envelop/suffocation/subsume suite
* DR/slashing
* not sure if sponges are plants, but possibly plant traits, immune to mind affecting abilities (and possibly visual effects - no eyes, or if it photosynthesises it might have vulnerability to visual effects/light spells OR gain power from light!)
How fantastic do you want it?
I love the idea - you should stat it up and submit it to Wayfinder #8 - the theme is nautical/oceanic and the deadline is Oct 12 I believe...
Dunno but you need to show us a picture of one.
http://www.dedleg.com/wordpress/wp-content/uploads/2010/08/carnivorous_spon ge.jpg
That's what a normal sized one looks like.
Here's one I found just now:
Carnivorous Sponge with crazy jaw like "spicules"
So a monstrous carnivorous sponge might have:
Deadly spicules These sharp toxin infused growths cause bleeding damage and poison (x blah blah blah).