An old NASA Tech Briefs article from 1995 discussed work done Marshall Space Flight Center researchers to see how various substances — including caffeine — affected spider web patterns.
To be more specific, they exposed spiders to a range of different chemicals, including caffeine, marijuana, and Benzedrine (amphetamine) and recorded how they spun their webs under the influence of each of those substances. Read more for another video and additional information.
“Spiders typically spin webs by producing silk from their silk glands with the help of their spinnerets, which are special organs that allow them to decide what type of thread they need at various points. The NASA researchers found that the more deformed the web looks compared to a normal web, the more toxic the chemical is,” reports Business Insider.