That effect happens if you use the false shield called "alucart shield". Its description should be 'resembles family heirloom' or shield or something. Dunno if it wasn't translated correctly or something in the psp copy, but its stats are very low. The real shield is somewhere in the inverted castle.
The real one will make a flash, then you'll be dealing massive damage to anything you touch with the shield, and every hit will also work like soul steal.