The Burglar

The Burglar is the first villain Spider-Man ever encountered. He is the criminal who killed Uncle Ben.

History
When this unnamed criminal broke into the house of May and Ben Parker, he was frightened by Ben and shot him. The bullet killed Ben, whiched caused his nephew Peter to capture the burglar as Spider-Man, starting his superhero career.

He later returned in an alliance with Mysterio. When Spider-Man appeared to thwart them, the burglar died of a heart attack.

Spider-Man Trilogy
The backstory of the Burglar is very similar towards the comics, though there are several differences as well. For one the Burgler does have a name; Dennis Carradine. Another difference is that he was partnered with another criminal named Flint Marko.

After Spider-Man won a wrestling match, the manager refused to give him the reward money. Shortly after, Carradine appeared and stole all of the manager's money, with Spider-Man letting him go. Some time later, Parker found a bunch of people in a crowd. There, he found Uncle Ben on the ground. The Police told him that he had been shot by a car-jacker. When Uncle Ben died in front of Peter, Parker went after the man who killed Uncle Ben. It turns out that the killer was the same person that ran passed him. Just when he was about to kill Parker, Parker grabbed his arm and snapped his bone. Frightened, Carradine backed up and fell through a window killing him.

A few years later, Parker and Aunt May were informed that Dennis Carradine wasn't the true killer. Instead it was his partner Flint Marko who murdered Uncle Ben. Near the end, Sandman told what really happened when Uncle Ben died. When Marko tried to get Ben to give him the car, and Uncle Ben replied, "Why don't you drop the gun, and go home?" Touched by the man's sympathy, Marko almost agreed. When Dennis ran by with the money, he bumped into Marko, which caused him to accidentally shoot Uncle Ben in the chest. Marko tried to help Uncle Ben, but Dennis abandoned Flint.

The Amazing Spider-Man
The burglar was seen behind Peter as he was buying a bottle of chocolate milk in a grocery store. He made a mess, causing the clerk to clean up leaving the cash register unguarded. He steals the money from the register and just like the first movie, Peter let him go after he was short-changed on buying chocolate milk and the clerk wouldn't let him take two pennies to pay for it. The burglar ran and bumped into Uncle Ben, who was looking for Peter. Ben saw that he dropped a gun and tried to fight it away from him, but the burglar shot him dead. Police then gave Aunt May and Peter a sketch drawing of the burglar in case they see him. He has long hair, a goatee, and a yellow star tattoo on his left wrist. It was Peter's hatred of the burglar that caused him to hunt down anyone who looked like him. As of now, he is still at large.