The US Taxpayer Party comes to mind.
In 1996, one of the local San Diego "pro-family" outfits set out to deliberately split the vote, with the *DECLARED* intention of electing a radical pro-abort and pro-gay-marriage candidate in my district--to "teach the Republicans a lesson."
They commissioned some push polls to clobber the GOP candidate (a fiscal conservative who didn't perfectly hew to the "pro-family" group's agenda), and then pushed a former bus driver running on the USTP ticket as their candidate.
The vote for the USTP candidate was about 0.5% higher than the Democrat's margin of victory.
And, what happens in 2002? The exact same scenario that they employed in 1996.