Deja wanted eyes on him. Deja wanted attention. Deja would do anything to get it.
The Supermental works like this- when one has it, if one has a thought, the thought becomes reality. If Deja wanted, say, a cake; he would believe he had a cake. Then, the world would ripple and change itself, and though he would not remember going to the store and buying said cake, the clerk would remember him coming in and buying said cake, and even what kind he got.
In essence, instead of the world running on 1+1=2, it would run on 2=1+1. Things happened subsequently because Deja wanted the end result to happen. All because of the Supermental.
And one day, a brat of a kid wouldn't listen to him. Mocked him with a confidence a kid their age shouldn't have. Maybe Deja shouldn't have done it, what he did, but it didn't matter now. Deja was angry at the kid, more furious than he has any right to be.
And he wanted the kid to hurt.
So he made them hurt.
Nothing that would kill them, but definitely hurt, possibly even affect them for life.
He decided on them losing a foot. So Pent lost their foot.
Days went by, and suddenly in the news, there was where a child had gotten themself stuck in machinery. They tried with all their might to pull themself free, but only managed to mangle their foot further. They were found by their friend passed out from shock.
There were surgeries, procedures of all kinds done, but 3 months later, nothing had gotten better, only worse. They give the kid another option to fix it, but Deja didn't ever care enough to remember it. Besides, the kid chose the amputation option anyway.
So, the kid loses the foot. They learn slowly, so godforsaken slowly, how to walk with a prosthetic on. Deja grins in a wicked way when he hears about it.
He got what he wanted. The kid lost the foot, and the world rippled to right itself on how it had happened. Deja spares a glance at the Supermental in his hands as he reads over the news again, and breathes in deeply, feeling it's power in his veins, and grins.