Basilisc lairs have the best loot! Sometimes more than you can carry! Entrance is on the surface in the Mining Dimension (Red Ant). Kinda pyramid shaped. Can you get through the maze without cheating? Of course, you need to defeat the Basiliscs before you can grab the loot. He seems to like Jungles too. The Basilisc drops all sorts of Emerald items.
You'll need a Basilisc Scale for Big Bertha!
Can cause poison and slowness.
How to Kill
From a distance, preferably.
Found: Mining Dimension, and Jungles
Drops: Emerald items & scales