Waylaying Time Waster: Tecuciztcatl
Enter Tecuciztecatl, the Lord of Snails.
In The Hidden Shrine of Tamoachan, he is a Large Monstrosity, neutral in alignment, amphibious and able to spit acid (literally).
He's here to way-lay and waste the time of any passing adventurers, letting the poisoned air of Tamoachan's Shrine suffocate them if he can't be moved to trick and thus kill them himself. "..quite the boaster," dedicates Portal - if fought, he will surrender, bargain, or flee.
He's an interesting character in Aztec Mythology, though the Aztecs don't seem to have been any kinder to him than Wizards of the Coast. He sets his sights on becoming the Sun, but when asked to sacrifice himself to a great fire, he is beaten to it by another god, Nanauatzin, who thus becomes the Sun in his place. Tecuciztecatl, glowing dimly, instead becomes the Moon.
Maybe some passing adventurer will finally motivate Tamoachan's Tecucizetcatl to make good on his dreams. Maybe not.
He appears in Chapter 3, Episode 2 - Slugs and Kisses. Click here to listen.