dream pun:

A guy goes to a psychiatrist. 

"Doc, I keep having these alternating recurring dreams.

First I'm a teepee, then I'm a wigwam,
then I'm a teepee, then I'm a wigwam. 

It's driving me crazy. 

What's wrong with me?"

The doctor replies, 

"It's very simple. 

You're two tents (too tense)."

Puns in dreams--visual as well as verbal. Ann Faraday pioneered the study of dream puns; she argues in "The Dream Game" that such puns aren't meant as disguises (Freud's idea), nor are they idle associations (Havelock Ellis); they often make a sharp point, one hard to make any other way. Their humor is useful: it sweetens awkward truths, to coax the reluctant conscious to look! Bad jokes often relax a skittish audience. And isn't the waking mind about as skittish as you can get?

This list also includes a related phenomenon, mondegreens: meaningful mishearings. The word is itself one; as a child, newspaper columnist Jon Carroll heard a folksong as: Lord So-and-so had died, and Lady Mondegreen. Years later he learned the line ended and laid him on the green. Examples include As a Hillsborough Child, He has Repented, and God Dressed Ye, Mare.

 http://www.worlddreambank.org/2/2PUN.HTM