When you give a spider a cookie...it will weave webs that look as though they were built by a creature missing a good-sized chunk of brain. At least, it will if that cookie contains mescaline, a favorite drug from the '60s (my uncle used it during his stay at a hippy commune to 'help' his tuba playing). Now, you might be wondering why such a strange scenario would ever arise, that anyone would want to create inebriated arachnids.
The experiments on the effects of drugs on spiders began in 1948 when zoologist H.M. Peters was having difficulty conducting his regular studies on the animals. The spiders tended to spin their webs during the early hours of the morning. Rather than sacrifice his own sleep to research, Peters followed the advice of a colleague and tried giving the spiders a dose of amphetamine. Although the arachnids continued their same nighttime habits, something else changed.
Depending on which drug the spiders were administered, they created radically different webs. The mescaline spiders, for example, made webs that appeared only half finished. This was due to the fact that the administered drug weighed its body down, making more web necessary for any movement. Other substances tested include LSD and caffeine, that latter causing the insects to construct extremely irregular webs (depicted here). The results of the experiments can be read about in much greater detail in "The Biology of Spiders" by Rainer F. Foelix.