Inventions created to be used for something else, but unexpectedly turned into a completely different product.

Baby head mask

Batman backpack

Batman Motorcycle helmet

Custom made lightsabers

Cut of meat dress

Flip throwable spectral light

Hairy chest sweater

I'm watch

Looper portable resort

Never wash me shirts

Predator helmet

Sand free beach mat

See through bottom canoe

The fat magnet: Removes excess fat from greasy food

The TRON light cycle

Zombie apocalypse bedding

Via dudeiwantthat.com

Or probably more of first world problems solved...

Via smosh.com

Pool table detects the ball, cue, and table and predicts where the ball will go

Ultra-Ever Dry is a superhydrophobic (water) and oleophobic (hydrocarbons) coating that will completely repel almost any liquid. Ultra-Ever Dry uses proprietary nanotechnology to coat an object and create a barrier of air on its surface. This barrier repels water, oil and other liquids unlike any coating seen before. The other breakthrough associated with Ultra-Ever Dry is the superior coating adherence and abrasion resistance allowing it to be used in all kinds of applications where durability is required.