Fire ants have arrived. Let’s make sure rock snot and murder hornets don’t

October 30, 2026 — 5:12pm

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Every Halloween, we invite monsters into our homes. Vampires, zombies, murderous clowns – all reassuringly imaginary. I find it harder to be frightened by them these days. I spend too much of my working life contemplating creatures whose real-life talents would be rejected by a horror screenwriter as excessive.

An enormous “murder” hornet whose sting has been compared with having a hot nail driven into your flesh. An alga called “rock snot” that can smother riverbeds in great mats of slime. Or how about a beetle the size of a sesame seed that carries a fungus capable of killing magnificent old trees. Welcome to my nightmares.

Having spent decades working on invasive species and extinction, I am frequently asked which potential invaders worry me most. It is a surprisingly difficult question. Thousands of species native to somewhere else could cause serious harm if they arrived here, and global trade and travel provide ever more opportunities for them to hitch a ride.

But in honour of Halloween, here are a few inhabitants of my ecological chamber of horrors.

First, rock snot (Didymosphenia geminata).

Urgent biosecurity review after site of........

© The Sydney Morning Herald