Fix vampires shifting into fog clouds as an escape method because this doesn’t currently work with fog clouds being slow and easily killed.

• Normal fog clouds can still be slow, but vampshifted fog clouds should have their regular form’s speed.
• Fog clouds in general should be very hard to land a hit on, with “your attack passes harmlessly through” like a ghost nearly all the time (allowing critical hits only?), or all of the time, if you are not engulfed. Fog clouds that are fleeing, like vampires running away, will not engulf the player.
• If a vampshifted fog cloud is pinned down and has nowhere to go, it can pass through the squares of a number of monsters blocking its way and land somewhere else, provided that space is within a few spaces. This prevents the player from trapping it in a corner and beating it to death.
• At some point, the vampire must turn itself back to normal, and not stay in fog cloud form forever.