This happens to me all the time. I run into something that suggests an analogy, but I can't come up with it. So I file it away for another day.
There is a species of red ants whose grubs are devoured by a large blue butterfly. The butterfly lays its eggs on thyme flowers and the caterpillars fall to the ground after hatching. They secrete chemicals and even make noises that make the red ants believe they are wayward grubs. The ants mistakenly carry the caterpillars to their underground homes and keep looking after them even though the adopted monsters gobble ant grubs for 10 months before forming a chrysalis and flying away as adult butterflies.
Ant grubs? Those are baby ants!