Visible crew/equipment: Near the beginning when the men are hauling the equipment to their camp, you can see a crew members hand in the bush literally toss the fake giant spider on top of the passing equipment. (00:13:10)
Visible crew/equipment: When the dog and the cat run out through the dog flap, you can see the puppeteer moving behind the flap handling the spider. (00:18:55)
Visible crew/equipment: When the explorer goes up into the loft to find the king spider, he taps the fake web string, says 'suppers ready" and then the fake spider dramatically shoots out from a tech wire 'screaming", and attacks him. (01:49:24 - 01:49:50)
Visible crew/equipment: Near the end when the doctor and his family are getting attacked by the spider's, half are CGI and the others fake as you can see the Tech wires making them move. Then when he's lying on the floor collecting himself, there's a pulsating sack in the corner, with a fake spider leg sticking out.
Answer: It definitely wasn't one of the offspring, as you can see when it jumped out at him that it was a very large spider, likely the general since they mentioned the queen would be guarding the egg sac in the wine cellar to defend it from other spiders.
Phaneron ★