No worries.  I'm assuming he's young.  It's just the colors that has his attention.  You can easily replace it with brightly colored video games.  We've all been there.

If I may, I suggest Dungeon Defenders.  You'll have fun for a while and it's very colorful.

Whatever you do, do not show him the brony threads on this forum.

Don't get after him too much for it. If he thinks you or anyone else is really bothered by it he'll make it an even bigger part of his identity just to test the limits.

The brony friends I have sometimes say they like it because it reminds them of old school cartoons that aren't around anymore. Maybe introduce him to something actually old school and more masculine, like G1 transformers or something, to try and subtly get him off it.

Pretty much this ...

Uhm, so? I don't see the problem.

Lord Xia started out as a brony... see what you have to look forward to?  He'll want lavendar ponies in his video games.

Well said. For our own kids, we decided long ago that if it ain't illegal, let them go ahead. Doesn't mean we didn't teach manners and such, we run a pretty strict shop. But judging or trying to decide for your kid what he wants is out.

Trojasmic: 

He'll probably get over it by himself. But it might mean he's lacking in social interaction, a lot of bronies are. If that's the case, try getting him into some organized group that he'll enjoy - a sport would be the traditional example of this but any activity in a group setting is fine. Whatever you do though, don't make a big deal about it. 

You have my condolences as well. Not exactly the thing I'd want my kid involved with. But sign him up for baseball or some manly sport quick or get him to a strip club quick!!

Works for me!

I don't have a television and have not had one for about 15 years. I was like ,wtf is a brony, so I googled it, SORRY MAN, my condolences. Wear sunglasses ans say its your nephew! Just kiddin. Jafos right, could be way worse.

Many do recover if they have the constitution to be rigorously honest with themselves.  Allow him to express his Broniness with others of his ilk, and encourage him to attend a Brony Anonymous meeting in your local vicinity.

You could always use the Ninja legend solution Frogboy.

Legend has it that when a widowed mother had no other recourse, she would taker her infant son to the Ninjas.  They would throw the child into a well.  If the child swam, he was fetched out and began training in the ways of ninjitsu.  If not...well, in either case, the mother never saw him again.

You will have to find the ninjas yourself though.

Rainbow Dash backpacks are on sale at Welovefine.com. Just saying. You know, with Xmas coming and all. (Its what my bf wants ).