How can a Sphere of Annihilation be detected, and how can it be “disarmed”?

Question

I'm reading the DnD Essentials DM Book, and on the Sphere of Annihilation stat block, it mentions several things I don't exactly know how to read:

• The sphere has "Detect automatic". Does this mean it is automatically detected, or evident?
• It has XP 15000, but no means of defeating it or disabling it, the only countermeasure stated is controlling it. Plus, it is immune to attacks.

How exactly do you get experience off of this trap? Or you don't, and it's just a very nasty trap? I do remember the iconic Order of the Stick comic "oh man, Sphere of Annihilation in the statue's mouth. That never got old".

EDIT I couldn't find references to "Detect: automatic" in the RC either, under Traps or in the Index. If anyone can point to a specific resource...

Answer 1

You are right, the stat block is a bit weird. I'd suggest using the trap as presented in the Dungeon Master's Guide. It is also the current version in DDI, so it is easily arguable to be the "correct" version.

Here are a few of the things from the original that were changed (for the worse IMHO).

• Perception: No check is required to see the sphere
• Arcana (DC34): The character recognizes the sphere's nature
• Countermeasures: Destroying or disenchanting the talisman is the only way to destroy the sphere. The talisman has AC 38, other defenses 35, hp 200; resist 15 all.

As for XP, you do not need to destroy the sphere to gain the XP. The XP is gained for successfully completing the encounter. Usually that will mean getting by or past the sphere. See the first sentence of the Traps and Hazards section in the Dungeon Master's Book:

the best way to counter a trap or hazard is to avoid it