You would not be the first to ask : What is this?
And they do not appear every year.
But after very heavy rainfalls I encountered several of these creatures on my workbench and around the workshop.
These hairy black caterpillars are the larvae of night-moths and they are carrying their own eggs on their backs. What looks like white elonganted rolls of cotton wool are their young ones.
And there she is falling off the work-bench. I found they did not really have a good sense of direction.