Could it be that glitches have found their way into even the newest Pokemon games? I can neither confirm nor deny these rumors, as I don't own a copy of Diamond or Pearl. There are some YouTube videos below that seem to confirm the existence of a strange new glitch...
From Saito of the Desert: "Okay, now, I'm not 100% sure about this, as I don't own either of the games yet. But my friends have both, and apparently there's a "migrating" feature that lets you transfer Pokemon from your old games onto that one, and I was wondering, if you have them... do you think it'd be possible to get the glitchy ones transferred as well? You might want to look into that one."
From tetsuo_27: "I don't know how this happened but somehow I encounted a Missingno like
Pokemon on Pokemon Diamond of course I was using an Action Replay to try and
capture any pokemon I might have forgot one code for the Wild Pokemon
Modifier Code anyway here's a link to see it in action."
From liz: "There is a new Missingno, and he comes in Diamond/Pearl! Missingno is relatively easy to get, all you need to do is get in a double battle with only one pokemon. Missingno's sprite is three white bars next to each other, is shiny, and causes some strange glitchy effects."
"I have heard of a new MissingNO! He can be found on Diamond and Pearl by getting into a double battle with only one Pokemon. He has no name, no health, level 0 (just like the (?) glitch in RS) and his sprite is three white bars next to each other. D/P MissingNO is Shiny, and can supposedly be trained. This was found on the Nintendo forums, here is a link to it if you want to read more.
From Max: "Hello it's me, Max, and I've bought a action replay DS not too long ago. And I found two new glitch pokemon and the return of two in Pokemon Diamond and Pearl! and I'm going to tell to how to find the 4 glitch pokemon!
Glitch Pokemon One: DP Wild Egg: Use both the 999 Leftovers code and the wild pokemon modifer code, I'll tell you both of those codes at the end, Once you do that start the game and hold L+R at the SAME time, Then go to your items and see if you got the Leftovers first, If you didn't, hold L+R again once you do that throw away enough to get 494 leftovers, and then go run around in grass holding L, Once you find it (you may not find it as the first you see.) run or beat it, Catching it will freeze your game. and thats all you need to do!
Glitch Pokemon Two: DP Bad Egg: Do the as before only discard enough to get 495. it has the same side effects as the Wild Egg.
Glitch Pokemon Three: Glitchy Suicune: I have no clue how I got this but I think its punishment for using too many cheat codes at once, I found it in box 1 slot one and Its nickname is ?????? and it's OT is just a bunch of glitchy things. its ID No. is 00000 it says it's a suicune and it's pokedex No. is 245 yet I didn't even have suicune in my pokedex! it's level is 1 and it was caught in some odd pink pokeball with 2 blue stripes on each side! It says lonely nature and it was found on January 0, 2000, How is that possible? pokemon pearl was in stores in 2007! (in japan it was released in 2006) and it says it was found in the mystery zone which you could access by using the WTW code and going through the barriers! and it was met at level 0 and it likes spicy foods, all of it stats are 6 but not the level, hit points, and Sp. Def! the level is one, the hit points are 13, and the Sp. Def is 7! it says its abilty is Drought, its only move is transform which has 99/16 PP (No Joke!) and it works fine. it has okay contest stats. and it has no Ribbons!
Finally, the one you've been waiting for is: THE DP MISSINGNO! first of all to get of all to find it use the wild pokemon modifer code and start the game and hold L+R at the SAME time and get rid of ALL your items in your items pocket (Don't save or they'll be gone for good) and hold L down and run in the grass and you'll find it! its name is ------------ (I can't remember how many -'s it was but it was alot) if you catch it it will display its pokedex listing and your game will NOT freeze, However you cannot use it at all. you can only see it when your deposting pokemon, its icon will be a white ?.