Hmm? Oh, that's relatively simple - though it does depend on the type of dream. If my arrival is unwilling? Typically, I'm looking for a source. Tearing away or unmaking whatever someone left to leave another in that state, or that creature itself...

[His gaze darkens when he talks about it, the friendly whimsy draining out of his voice to be replaced by venom.]

There are quite a number of creatures that abuse the subconscious of others for their own gain, or simply to harm without reason. For me, as a creature who can only truly exist in the subconscious of others, that's no different from salting the earth.