One day, just after they had finished their D.A.D.A. OWL exam, they saw Snape sitting down not very far off from them.  The sunlight was dazzling on the smooth surface of the lake, on the bank of which the group of laughing girls who had just left the Great Hall were sitting, with their shoes and socks off, cooling their feet in the water.

Remus had pulled out a book and was reading. Sirius stared around at the students milling over the grass, looking rather haughty and bored. James was still playing with the Snitch, letting it zoom further and further away, almost escaping but always grabbed at the last second. Peter was watching him with his mouth open. Every time James made a particularly difficult catch, Peter gasped and applauded. 'Put that away, will you,' said Sirius finally, as James made a fine catch and Peter let out a cheer, 'before Wormtail wets himself with excitement.'

Peter turned slightly pink, but James grinned.

'If it bothers you,' he said, stuffing the Snitch back in his pocket. 'I'm bored,' said Sirius. 'Wish it was a full moon.'

'You might,' said Remus darkly from behind his book. 'We've still got Transfiguration, if you're bored you could test me. Here ...' and he held out his book.

But Sirius snorted. 'I don't need to look at that rubbish, I know it all.'

'This'll liven you up, Padfoot,' said James quietly. 'Look who it is.' Sirius's head turned. He became very still, like a dog that has scented a rabbit.

'Excellent,' he said softly. 'Snivellus. Snape was on his feet again, and was stowing the OWL paper in his bag. As he left the shadows of the bushes and set off across the grass, Sirius and James stood up.

Remus and Peter remained sitting: Remus was still staring down at his book, though his eyes were not moving and a faint frown line had appeared between his eyebrows; Peter was looking from Sirius and James to Snape with a look of avid anticipation on his face.

'All right, Snivellus?' said James loudly.

Snape reacted so fast it was as though he had been expecting an attack: dropping his bag, he plunged his hand inside his robes and his wand was halfway into the air when James shouted, 'Expelliarmus!'

Snape's wand flew twelve feet into the air and fell with a little thud in the grass behind him. Sirius let out a bark of laughter.

'Impedimenta!' he said, pointing his wand at Snape, who was knocked off his feet halfway through a dive towards his own fallen wand.

Students all around had turned to watch. Some of them had got to their feet and were edging nearer. Some looked apprehensive, others entertained.

Snape lay panting on the ground. James and Sirius advanced on him, wands raised, James glancing over his shoulder at the girls at the water's edge as he went. Peter was on his feet now, watching hungrily, edging around Remus to get a clearer view.

‘How'd the exam go, Snivelly?' said James.

'I was watching him, his nose was touching the parchment,' said Sirius viciously. 'There'll be great grease marks all over it, they won't be able to read a word.'

Several people watching laughed; Snape was clearly unpopular. Peter sniggered shrilly. 

'You--wait,' he panted, staring up at James with an expression of purest loathing, 'you-- wait!'

'Wait for what?' said Sirius coolly. 'What're you going to do, Snivelly, wipe your nose on us?'

Snape let out a stream of mixed swear words and hexes, but with his wand ten feet away nothing happened.

'Wash out your mouth,' said James coldly. 'Scourgify!'

Pink soap bubbles streamed from Snape's mouth at once; the froth was covering his lips, making him gag, choking him--'

'Leave him ALONE!'

James and Sirius looked round. James's free hand immediately jumped to his hair. It was one of the girls from the lake edge. Lily came rushing over

'All right, Evans?' said James, and the tone of his voice was suddenly pleasant, deeper, more mature.

'Leave him alone,' Lily repeated. She was looking at James with every sign of great dislike. 'What's he done to you?'

'Well,' said James, appearing to deliberate the point, 'it's more the fact that he exists, if you know what I mean ...'

Many of the surrounding students laughed, Sirius and Peter included, but Remus, still apparently intent on his book, didn't, and nor did Lily.

'You think you're funny,' she said coldly. 'But you're just an arrogant, bullying toerag, Potter. Leave him alone.'

'I will if you go out with me, Evans,' said James quickly. 'Go on ... go out with me and I'll never lay a wand on old Snivelly again.'

Behind him, the Impediment Jinx was wearing off. Snape was beginning to inch towards his fallen wand, spitting out soapsuds as he crawled.

'I wouldn't go out with you if it was a choice between you and the giant squid,' said Lily.

'Bad luck, Prongs,' said Sirius briskly, and turned back to Snape. 'OI!'

But too late; Snape had directed his wand straight at James; there was a flash of light and a gash appeared on the side of James's face, spattering his robes with blood. James whirled about: a second flash of light later, Snape was hanging upside-down in the air, his robes falling over his head to reveal skinny, pallid legs and a pair of greying underpants.

Many people in the small crowd cheered; Sirius, James and Peter l roared with laughter.

Lily, whose furious expression had twitched for an instant as though she was going to smile, said, 'Let him down!'

'Certainly,' said James and he jerked his wand upwards; Snape fell into a crumpled heap on the ground. Disentangling himself from his robes he got quickly to his feet, wand up, but Sirius said, 'Petrificus Totalus!' and Snape keeled over again, rigid as a board.

'LEAVE HIM ALONE!' Lily shouted. She had her own wand out now. James and Sirius eyed it warily.

'Ah, Evans, don't make me hex you,' said James earnestly.

'Take the curse off him, then!'

James sighed deeply, then turned to Snape and muttered the counter-curse.

'There you go,' he said, as Snape struggled to his feet. 'You're lucky Evans was here, Snivellus-- '

'I don't need help from filthy little Mudbloods like her!'

Lily blinked.

'Fine,' she said coolly. 'I won't bother in future. And I'd wash your pants if I were you, Snivellus.'

'Apologise to Evans!' James roared at Snape, his wand pointed threateningly at him.

'I don't want you to make him apologise,' Lily shouted, rounding on James. 'You're as bad as he is.'

'What?' yelped James. 'I'd NEVER call you a--you-know-what!'

'Messing up your hair because you think it looks cool to look like you've just got off your broomstick, showing off with that stupid Snitch, walking down corridors and hexing anyone who annoys you just because you can--I'm surprised your broomstick can get off the ground with that fat head on it. You make me SICK.'

She turned on her heel and hurried away.

'Evans!' James shouted after her. 'Hey, EVANS!'

But she didn't look back.

'What is it with her?' said James, trying and failing to look as though this was a throwaway question of no real importance to him.

'Reading between the lines, I'd say she thinks you're a bit conceited, mate,' said Sirius.

'Right,' said James, who looked furious now, 'right--'

This thought of thing happened often, sometimes with Snape attacking James instead of the other way round.

One day, Sirius decided to play a prank on Snape. He told Snape how to get into the shrieking shack from the whomping willow. Of course Snape tried it and if he and if he had reached the shrieking shack, he would have met a fully grown werewolf, which would have probably killed him. Luckily, James did something amazing and surprising- he saved Snape's life! He went down the tunnel to the shrieking shack and brought Snape back before he could get hurt, but Snape had glimpsed Remus and knew that he was a werewolf from that day on.