Antisemitism as a phenomenon is not only alarming but also very puzzling, especially in countries which pride themselves on having won the war against the Nazis; whose principal educational institutions are generally very disapproving of all forms of racism; where people who regard themselves as anti-racist often deploy the rhetoric of ‘Never again’. [1] Even more puzzling is the fact that antisemitism is currently on the increase, in many places by leaps and bounds. [2] The spike started immediately after 7 October, before a single Israeli army boot entered Gaza, so it wasn’t prompted by the war in Gaza, though it was certainly greatly increased by the armed conflict. It looks as if the very sight of atrocities being committed against Jewish civilians was enough to make some people – on occasion, rather a lot of people – hate Jews and want to harm more of them. No doubt there are many different causal forces producing this result, and much thought and discussion and research will eventually be needed to pinpoint the most important ones. But right now, to help us understand and even just to describe this phenomenon, it may be useful to reach for a metaphor, since we often try to understand a puzzling phenomenon by comparing it to another one which we do understand a bit better, and hope thereby to get a better grip on the less comprehensible event.