Padfoot and Wormtail
Peter Pettegrew: small, ignorant boy, nervous, jumpy man, and complete and total traitor.
The one who had followed the more popular boys around, who had followed anyone who could give him the smallest amount of power and protection. And then betray them if they found someone who could give him these things in larger amounts.
The most cowardly person who ever managed to get himself into Gryffindor.
The one who he had trusted with Lily and James's life.
They had died as a result.
That was why he, Sirius, was had tracked him down.
It was almost too easy. It seemed as though Pettegrew had gone out of his way to walk in mud, through patches of sand, anywhere he could leave very obvious footprints. All Sirius had to do was follow them.
A rat scurried along just ahead of him. He would recognize that rat anywhere, with the wormlike tail that had given Pettegrew his nickname.
Wormtail, a Marauder's name, a name which the rat did not deserve.
Sirius transformed into a dog and set off after the rat. When he was close enough, he pounced, catching the tiny creature underneath two huge, black paws. He transformed back into a human, ending up on his hands and knees with a rat pinned underneath him. He took out his wand and muttered a spell that would force Pettegrew to transform back into a human. Immediatley, Peter started to shout, "You betrayed them! Lily and James! They were our friends, Sirius, our friends! Why would you do such a thing?" Sirius raised his wand, ready to curse the rat, but Sirius was not fast enough. The rat drew his wand and shouted, "Reducto Maximus!"
The street itself exploded, and Sirius was thrown backwards. He just managed to crawl away from the falling rubble in time for it not to crush him into a pancake. When he was sure that there was no mare falling rubble, Sirius stood.
Ministry officials were coming his way. One of them roughly grabbed his arm. "You're coming to Azkaban," he said gruffly. "You're insane, Black. You blow up the street… you'll be pleased to know there were no survivors—"
Sirius did not hear anything else that was said. He started to laugh, a loud, maniac laugh; the rat, the traitor, the reason Lily and James were dead had joined them in death, finally gotten what he had deserved…
Meanwhile, Peter Pettegrew, who was very much alive, pulled out a knife, and, knowing that the Ministry would be suspicious if they found no trace of his remains, cut off his index finger. He let out a gasp of pain, a gasp that became a squeak as he turned into a rat, and set off to find his master and help him rise back to power.