10. The Undertaker
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On the all-time list of bad wrestling gimmicks, you'd think that 'wrestling mortician' would be at or near the top of the list. First of all, why would someone in the lucrative funeral home business need to wrestle in the first place?
In spite of the characters' perceived silliness, Undertaker has become one of the most beloved performers in all of wrestling history. Taker stuck with the gimmick stubbornly, even as his contemporaries evolved into more 'realistic' characters.
Over time people responded to Taker's awesome athleticism and unwavering poise, turning the villain into a hero beloved by all. A wrestling funeral home operator sounds silly, even embarrassing, but Taker managed to elevate it to perhaps the most successful wrestling gimmick of all time.
There you have it; ten gimmicks which should have been failures, but became successes anyway.