UKIP is "dormant" like the Black Death, its general secretary said after it suffered heavy losses in the English local elections.
In the 150 council elections UKIP won three seats - including two in Derby - and lost 123.
But general secretary Paul Oakley said it was "not all over at all" for the Eurosceptic party, which has suffered since the Brexit vote in 2016.
"Think of the Black Death in the Middle Ages," Mr Oakley said.
"It comes along and it causes disruption and then it goes dormant, and that's exactly what we are going to do."
The Black Death claimed an estimated 25 million lives, more than a third of Europe's population, between 1347 and 1351. Scientists have previously warned it could be lying dormant and could strike again.
UKIP leader Gerard Batten later said this would not have been his "choice of medieval historical analogy", adding: "We've certainly been a plague on the houses of the Tories and Labour, so maybe we can be a plague on their houses again."
He added: "I think things will change as we go forward and people realise they're not going to get the Brexit they voted for in 2016, when I think our support will build again."
“How helpful was it that Paul Oakley, your general secretary, described it as the Black Death for UKIP?” asks @jo_cobun— BBC Daily Politics and Sunday Politics (@daily_politics) May 4, 2018
“It would not have been my choice of medieval historical analogy. I would probably have gone for Robert Burns” @GerardBattenMEP#election2018 pic.twitter.com/S6MuKan4LE
Despite the local elections result, former deputy chairwoman Suzanne Evans said UKIP could still "put the cat among the pigeons".
She hailed the result in Derby, where the party unseated the Labour council leader, adding, in a reference to Brexit: "If UKIP does crumble I think you could still arguably make the case that it's been one of the most successful political parties in history."
UKIP had a good night the last time the seats were contested, in 2014, when the vote coincided with European elections, which it topped.
At the time it was led by Nigel Farage and was putting pressure on the government for an EU referendum.
But it failed to win a seat in last year's general election and has gone through a succession of leaders since the Leave vote.