Want to see what happened when the witches unleashed their spell? For me, it was towards de-aging.
Stiles, thankfully, wasn't touched and when suddenly there were 4 kids in the clearing, he immediately knew what was going on because he'd KNOWN Lydia as a kid, and she's exactly the beautiful girl he feel in love with.
Lydia is just as he remembers her, long reddish hair and soft eyes. Cynicism hasn't entered her life yet:
Lydia Martin (Miley Cirrus)
Then there is Chris Argent. He's the oldest of the kids right now, maybe 12 years old. There is no mistaking those sharp blue eyes and dirty blond hair. Just like the others he has no memory of how he got there, and he eyes everyone suspiciously (though the smile he gives Allison is gorgeous. He tells her she looks just like his cousin Amy).
Chris Argent (Colin Ford)
Boyd is a bubbly kid, all smiles and easy trust. From the start he shadows Derek, asking a million and one questions. It hurts Stiles' heart a little to see him like that, and he wonders what happened to harden him into whom he became.
Vernon Boyd (Anthony Michael Hobbs)
But the biggest shock is Peter, who was closest to the witches and was hit the hardest. He's this tiny thing, with a deliciously wicked smile but no malice at all. For some reason he clings to Stiles, who can't help to cuddle him. He sure hopes Peter won't remember a thing when the spell is reversed, or he'll never live it down.
Peter Hale (Thomas Brodie-Sangster)
(For the record, Derek is quietly freaking out but he lets the kids climb all over him with oceans of patience. It's ADORABLE and Stiles takes lots of pictures. For posterity.)