When a GM offers a GM Intrusion (GMI), it's usually something that adds a complication to the story or to your character to make things more interesting. The same thing happens when you roll a natural 1, but in that case, you don't receive extra XP.
For instance, you might make it to the top, but you might encounter an algae that attaches itself to you, dealing a certain amount of Might damage. Or in your haste, you might drop your weapon, rendering it useless until you retrieve it when you descend.
Usually, you don't know what sort of complication it will be until after you decide on whether or not to accept it. If you don't want to risk whatever the complication is, you can spend an XP to prevent the GMI.
Last edited January 11, 2016 3:31 pm