So I'm going to be a part of a campaign that will at the very least start in a swamp and was thinking of a thematic character. I then saw the death roll ability from the Crocodile domain and have become smitten with the idea of a grappling monk/druid.
Is this as stupid as it sounds? Any prestige classes or anything else that could help with this?
The party's going all orc so race is fairly locked in.
Can you be a Half-Orc? This will make some options a bit better and can still work thematically.
I am a big fan of the blight druid. You get some nifty domains, though croc is still fun, but blight definitely fits with swamp very well and you don't lose out on wild shape progression.
Monk/Druid work really well together. A monk level can add a bit of AC, extra feat and in this case you can grab both IUS and Improved Grapple with a monk dip and no other feat cost. Go tetori if that is your goal. Keep in mind you will still suffer the penalties of grappling which most of the other builds ignore.
Shaping Focus and Natural Spell are a good combo to keep your wild shape up despite the monk dip and to let you cast while in other forms. Powerful Shape will also be useful.
Druids and Monks are the best grapplers in the game -- Druids due to their ability to increase their size to ridiculous proportions, Monks because they have access to the Tetori archetype, which has amazing utility for grapplers (and because they can dimension door right into a wizard's face).
I'm not sure how a multiclass Monk/Druid would work... I'd say that your best bet is to get Shapeshifting Focus at level 5th after 4 levels of Druid, and then go full Tetori Monk.
Say "Crickey!' a lot.
Mauler Familiar (to make your familiar able to be a flanking buddy)
Shaping Focus, and Monastic Legacy are the 2 feats you MUST take.
Oh god, the face smashing as a (insert Huge animal) flurry of blows all over something for what, 3d8 a blow? (not sure what it should advance to, but you would want monk robes to further pump monk fists)
Probally run around as some Megafauna or Dinosaur for the Huge size. Friend has beastiarys, or I would look up some contenders. That said, a T-rex flurrying is a very funny mental image.