For the famous scene where Paul gets eaten by the Blob,
Donovan Leitch had to have a whole body cast made of himself because it would've taken to long to have him underneath it. Chuck Russell did not tell Shawnee Smith it wasn't really Donovan Leitch underneath the blob until filming on that scene began so he could get a true look of terror out of her. There were about 50 people running the animatronic man, but the blob covered the wires so Russell was easily able to conceal them until a few takes were done.