That happened to me too. I was facing....err...mutve bin Griever and i used Renzukoken, as you do, and Lionheart came up. As soon as it said Lionheart and blue electricity surrounded Squall, all the pixelated characters when weird and some of their pixels were black! They looked so funny when they were doing magic and the screen went close up to their faces. Anyhow, the weirdest part was I got rid of the pixels by summoning.....I summoned with one character to see wether it would go and it did, but only on the character that summoned. So i did it with the other: same. Griever took it off himself by doing shockwave pulsar and Squall was the only one left with black pixels and i left him like that ....it didnt change the end of the game at all....as soon as the battle was over he was back. It was definatly a weird moment tho.....and i agree that it has to be something to do with playing it on PS2 cause thats what it happened on.