this is a game

The bell tolls but the blob looks unchanged.  

Charles chill touch grasps the blob which has no reaction to its touch other then it darkens slightly in color...

Suri Mellow Katrina Pip your up

Mellow uses his last bit of spell energies to cast Guiding Bolt   To Hit:  18

Mellow gathers brilliant, radiant energy that blooms in his hands. With a sharp incantation and an outstretched finger, he launches a searing, celestial streak of light that crashes into the blob, leaving a dull glow on it's form and helping Mellow's companions to see their target.      13 pts of radiant damage  

 Mellow then suddenly vanishes.
((  Bonus Action:  Hidden Step ))

Suri moves a little bit forward and uses her Breath Weapon and acid hurls from her mouth in a 30ft line that's 5ft long.

DEX save 12 - 8 acid damage on failed save (4 acid damage on a succesful save)

Pip is flummoxed that his bolt of fire seemingly did no damage to the creature, and he sees the damage that it is doing to his companions.  He touches his chest and mutters a few words, casting mage armor on himself, then looking to move up to 30 feet and find a spot of cover.  His AC increases to 15.  He tries to think out loud, saying to everyone, "Fire doesn't seem to hurt it, how shall we attack it?  Any ideas?"

Mellow hits the blob with pure radiance and the metallic goo immediately starts steaming… Suri’s well aimed projectile acid splashes over the creature which appears to vibrate in response.

Katrina then Xolan are up.

"Hold up!" Charles says (despite it being out of turn), "It's adapting to our attacks. I know both of my chill touches hit, and both of those guiding bolts hit too. But the second time we used them, they had less effect! And whenever we deal a new source of damage, it takes it full-on! We have to finish it off with one massive attack!"