Here's the breakdown:
* Teenage Peter Parker is a shy and nerdy science enthusiast.
* He attends a science demonstration at a high school where a radioactive spider escapes and bites him.
* The radioactive spider's venom mutates Peter's DNA, granting him superhuman abilities.
* These abilities include:
* Superhuman strength and speed
* The ability to cling to walls and ceilings
* Enhanced senses, especially spider-sense, which warns him of danger
This origin story has been adapted and changed over the years in different versions of the Spider-Man mythos, but the core elements remain the same: a radioactive spider bite and a young man gaining incredible powers.