What the Hell is That?!

Participants:
Rhea, level 2 Cleric
Violet, ECL 3 Cleric
Aeron, level 2 Warblade
Hussam, level 4 Wizard/MstrSpc
Victor, level 1 Warlock

Challenges:
6 CR1/3 Goblins
2 CR1 Lizardthings
1 CR3 Goblin Leader
3 CR2 Tentacles

Experience:
Aeron - 880
Rhea -880
Victor- 880
Violet -880
Hussam - 860

Treasure:
1200 gp for each from the City of Avalon as job payment.
Those wishing to take tunnel-goo-making grubs home may, although the grubs have now become intert die in 2 days.
Taking wall samples home is fine, although the 'goo' becomes hard and brittle and desintegrates turning to dust 6 days later, as the grubs haven't been around to keep it wet/working.
Everyone may notice the Goblin Leader's Breastplate, which had an unknown symbol on it, presumably of an "unknown god" the goblins and mastermind mage (and portal?) alluded to.

Summary:
After signing up for "civic duty", the party was sent out to look for some Goblins that had abducted a rich (and annoying) noble's daughter. They found a typical goblin cave, and after entering realized is was anything but typical. Strange worm/maggots had turned the entire place into some sort of alien tunnel, feeding off the rock and anything else to make the place as foreign as could be. After defeating a warped-goblin camp they were sent to find , they found the true source of the Evil.. A Mage of some sort had opened a portal to another, alien dimension. The portal produced tentacles as they approached, which attempted to fight the party off, but fled back to it's native realm after one tentacle heads was cut off, leaving them to watch the offending Mage flee, but only after he had activated a self-destruct mechanism from his place of total safety. He let them ultimately have the noble's daughter they were sent to find, as not the Mage but the Goblins had abducted her in an attempt to make some extra money. They fled as fast as they could, only to have the portal to the unknown dimension's altar and Mage's laboratory explode from the device behind them. In the end they achieved the goal at hand, if not after seeing some maddening things and disturbing visages first.

Final post for those who missed:
At Aeron's mighty blow, one of the heads comes off a tentacle and spews strange black goo everywhere. There's a terrible noise emanating from the portal as the beast seems to recoil and not seem sure what to do. After a moment, the tentacles recoil completely and fold back into the inter-dimensional rift. 'What…what are you doing!?" the mage cries out outraged. "You're fine, you can fight more!" After a pause he seems to have gotten his response. 'Not strong enough? I see…as you wish lord." He moves over to the generator on the podium and flicks a switch. Like a light going out, the portal suddenly dies. "You can have the girl," he says, "shes of little use to me now." He flicks another switch and the force wall suddenly begins to waver. "Oh," he says as he walks to the far side, "don't stick around too long. This generator is rigged to explode. Good luck getting anyone to believe you about what you think you've seen." He suddenly teleports out somehow, having been standing on a round disc presumably some sort of transport device." The force-wall then fails and the generator begins to make an angry whining noise. You'll find you have just enough time to grab the girl and make an escape, though the blast doesn't destroy the whole cavern, just a portion of it. As the bomb goes off the Grubs collectively seem to give up life, and as as you continue to flee hundreds if them rain from the ceiling on your heads, not dead but seeming to just have become inert. The last leg of your fleeing exit is a squishy one indeed, although the larger and all-destroying blast you may expect never comes.