The Klein Bottle is one of the 3 Forth Dimensional Objects.
How to obtain:
1: You will need more than 390 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 positive karma) or the painkillers (for negative karma) and he will give you a squegee. Then go to the third island behind the 11 Seven, and the Squegee kid will be there. Give him the Squegee and he will give you the Klein Bottle.