In Phantoms (1998) the "ancient evil" has one of it's drones provide a biological sample to Dr Flyte. It came out looking like maggots and then turned into a Gecko for a brief moment and then turned back into guck. Flyte was told to study it.
The team does just that, they study the sample and find it's similar to petroleum and come up with a way to destroy the creature.
Why did the ancient evil want Flyte to study it? What was the purpose? We know that it wanted Flyte to "write the gospel" but what does the sample have to do with that?