...but first, a couple of things:

Olan - Jarenion's got Turn Pebble to Boulder if that might be of any help... got a few other spells that might be effective in dealing with yon tentacle beasty, as well, but have some pondering to do before I commit the mana.

Which brings me to the second thing:

Roger - Would Stone Skin be of any use, here, in keeping the leeches from further digging in?

Stone skin would prevent the leeches from getting into you for awhile.

Stoneskin is pretty indispensable if you are a squishy mage.

No worried on the boulders. I'm just debating whether it's better to fire a bow or go all hulk smash here. Arien can obtain boulders, per the DM - no need to allocate mana to that.

Arien wanna rock.

...some of the options I'd considered for a "magical assault" on the tentacle beasty(ies) were:

1. Using Reduce to shrink the sucker down (maybe enough that it might fall out of the cavern roof all together and meet an unceremonious end under the boot heel of some random party member.
   
   
2. Wall of Stone could be used to "cover over" the part of the ceiling from which the tentacles are attacking from, perhaps? Possibly severing some or, at least, impeding them enough to make good our dash for the tomb.
   
   ...or...
   
   
3. FIREBALL!!!... Or, you know, something similarly nuclear... Assuming we get Ody loose and don't have him fried up like a bear roast in the blast radius.

I am open to suggestions, of course, and have considered a few other options (charm monster, mordenkainen's sword, etc) but the above were in my "top 3" first.

Reduce is clever, I like that.

But truthfully, this really does scream "kill it with fire" to me.

Assuming we can avoid barbequed bear.

Well, a quick look says to me that while tossing a boulder would be a lot of fun, it's probably a tactically better option to pull the old longbow. Same base damage, but the bow is enchanted, has a vastly better range, and Arien can fire more than once per round.

Oh DM, live forever. Does Arien get his strength bonus to damage with the bow, or no?

Werebears roasting on an open fire
Hot sauce dripping from their toes
Yuletide ursas fresh-filleted by the choir
They poked hot skewers through their noses.

No strength bonus with a bow unless specified at character creation

Okie dokie, artichokie!

If we can get Ody loose, we'll go for the "nuclear option" unless there are any objections.... aaaaaand, now that I've got an inkling of a plan I feel better about getting this post stitched up. Should have something by this evening or tomorrow morningish.

Trying to help him get loose, lets hope my aim is good

Max throws first axe, *Thuck* nails Ody in the back.

"Sorry!"

Max throws second axe, Cuts limb in two, drops Ody twenty feet to the jagged rocks below.

"Umm..Sorry again!"

Definitely an amusing image... buuuut also one that brings to mind the need to spare Ody that fall.

Hammer - can we have Fin ready with feather fall for this contingency or is/will flute playing be consuming the bard's time?

First you say you don;t want to BBQ the bear and then you say let's have him fall slower while we bbq him?

You people are watching too much Walking Dead.

But, you're right... feather fall might just keep Ody from falling fast enough to avoid being.... ahem... singed by a fireball. :/

You know what, though? If that happened we'd have a flaming bear!!! How cool is that?!?!?