Got closer and realized it was actually a moth, about the size of a bat, pink, and very fuzzy. So, not terrifying, but definitely out of the ordinary. It took us a little while to find what it was, but we've done so: it was an Emperor Gum Moth. Imported from Australia, these guys grow to a wingspan of about 15 cms, have soft feathery antennae and are generally considered to be relatively harmless to New Zealand.
So here's the wiki entry for them:
Opodiphthera eucalypti
Here's some photos found on the internet about them. Turns out they are kind of cute.
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