Answer: Silver Bullet
Explanation: A silver bullet provides an immediate solution to a problem, especially one that has been a persistent problem. Its origin is from folklore where silver bullets are used as a weapon against dangerous mythical creatures such as werewolves, vampires and witches.
In Information Technology, a popular book titled No Silver Bullet – Essence and Accident in Software Engineering explains that it is impossible to cut through the complexity of software development and each major improvement can only be achieved through incremental steps.