Find them in the wild

These are unpredictable, but they eat blue bottle jellyfish, so if you see lots of blue bottles then the chances are that you might find these guys too. They live on the surface of the water, out at sea and when the swell comes from the East they can get washed in. So my tip to see them is to go to the beaches at high tide, after big swell from the East (usually around December-March) and look for them on the shore. Be careful - handling the slug may cause a very painful and potentially dangerous sting.