I have a new party of three absolute beginners lined up for next saturday. I forgot the snails in the adventure though

at least 2 go unconscious and the other is heavily wounded

Snail's not even guarding anything, the party just saw it and decided to go berserk.

Damn murderhobos.

Add them in as wandering monsters. AC 16, 12 HP, 4' move

As it dies, it shapeshifts back into a human. He was meant to reveal the plot of the campaign, but now he is dead. FMDML!