The Interdimensional Space Time Continuum Bait-and-Switch Ground Rules

One of the most perillous moments in any D&D campaign is the Interdimensional Space Time Continuum Bait-and-Switch. If you do not know what that is, let me explain: It is when the players move into a different dimension and/or break in space-time such that things become Different to How They Were. Two examples from my own life: a - PCs are in a dungeon where they encounter a place where, due to a…