The Klein Bottle is one of the three 4D objects.
How to obtain:
1: You will need more than 400+ strength. Go to The Club on the third island and find a stick figure named Broski. He will challenge you to an arm wrestling contest and by winning he'll give you a Klein Bottle.
2: Find The Dimensional Drifter and buy the Klein Bottle from him from him for $100,000.
3: Go to Wally Mart, buy either a bottle of painkillers or a self help book, wait till evening, on the first island near New Lines Inc. there is the Suicidal Goth Dude. Give him either the self help book (for +Karma) or the painkillers (for -Karma) and he will give you a Squeege. Then go to the third island behind the 11/7, and the Squegee kid will be there. Give him the Squegee and he will give you the Klein Bottle.