A long time ago the Gallifreyians manufactured a "superhuman drug" which can slow down a person's perception of time. The drug is usually kept in a blue bottle but can also be stored in specially build host bodies. It is able to make one second seem like 100 years for the unfortunate victim to whom it is administered. An undiluted dose of the drug causes the senses to speed up trillions of times while the relatively "slow" body fails to keep up, resulting in paralysis; on the other hand, it is implied that a diluted dose of the drug can greatly enhance the user's reaction speed. It is even stated that a single droplet would have to be diluted 250,000 times to be suitable for use.