> this one failed you but was a near enough miss that you couldn't see it. What you were really looking for is the Red Queen

GP was looking for a specific term that they had heard before. It was co-/evolutionary arms race, and ChatGPT guessed it correctly.

Also GPT-4o elaborated the answer (for me at least) with things like:

    > However, the specific kind of equilibrium you're referring to—where neither side ever fully "wins", and both are locked in a continuous cycle of adaptation and counter-adaptation—is also captured in the idea of a “Red Queen dynamic”.

    > You could refer to this as:
      * Red Queen dynamics in plant-insect coevolution
      * A coevolutionary arms race reaching a dynamic equilibrium
      * Or even evolutionary stable strategies (ESS) applied to plant-herbivore interactions, though ESS is more game-theory focused.