What on earth is this?

Found it on my car. Its only 20-30mm long.

North east victoria

SA

Sydney Aus

I couldn’t open the door i was too scared so this is the only pic i got

It’s butt was huge lol

Same family of wasps that I posted video of a few weeks ago, where the male picked up the female from a piece of grass. This pair is a different species, but same family. But the female was much bigger than the thynnid females I've been rescuing from the swimming pool (see second photo for size comparison with my index finger).

When they had done their business, she kind of flicked off, then walked down the plant stem to the ground to look for a beetle larva to lay her egg in.

We have had a couple wasps inside the house and have found this by the back door.

We don't want to kill them if they are native and likely not to be a problem. But I know nothing about wasps and we have an 18 month old who is curious but I don't want stung :)

Thanks!