Depends on what method of shrinking and what materials the box is made of. If it's strong enough to harm you, possibly kill you, then horrifying; if it's not strong enough to harm you, no big deal.
being stuck under a house full of sewage leaks, fermenting trash, and heroin needles from junkies.
"I wasn't counting cards, I was cheating."
"Ugh. you give me hives."
"It's Tee-revor time!!!"