For me, the worst of the worst came during the early days of particle when they overloaded them. The La Nina, Trauma Response, Hammer 4D HPT, and Animal were all absolutely worthless for me. The Hammer Vicious gave me fits. With the box shine it went 50 feet and then banked straight left, leaving me more 2-8-10 combos than I care to remember. Then, when I knocked the shine off, it rolled immediately and did nothing down the lane. More recently, the Hammer No Mercy was an absolute dog in my hands as was the Deep Purple Taboo.

As others have said, I believe that just about any ball can work if the right matchup is found between layout, surface prep, bowler style, lane surface, and oil pattern. Sadly, I never found the right matchup with any of the balls listed above.

I'll have to say the Storm Dimension.  Not that it's a bad ball, but it is for me. 

MoRich Solid LevRG. That ball was a turd for me at two drillings and four surfaces on each drill. Never turned, puked at the pins too.

As a side note, I was very inexperienced when I got this ball, and had no strategy other than to grip it and rip it. Most likely this was my problem, not the ball's.

I've never owned a bad ball, or seen one frankly. I've seen a lot of balls that don't match up to a particular bowler's style, but I'd bet every single ball listed in this thread was used to success by someone else.

What's that say?

Unless it's egg-shaped or falls apart when it hits the pins, "bad" is very subjective.

Jmac, don't tell BrunsNick!

When a company cancels a ball and replaces it as fast as possible ahead of normal production because of its reception by the public and lack of sales its likely a bad ball. Never say say never on a bad ball. They are few and far between but they exist

A columbia high performance ball from two years ago.

I absolutely Could not stand my Ebonite Playmaker.  With and without a weight hole two different surfaces, two different houses.  Way too over under.

Lane 1 G-Force sucked for me as well. I don't think I was ever able to shoot 200 with that Piece.  That ball turned me away from Lane #1 as well.