User blog comment:IamJakuhoRaikoben/Chapter 411: Quid Pro Quo, Review./@comment-25111584-20141201135113/@comment-25111584-20141201142408

@B214: If the Spell was incomplete or not cast properly? I'm not even sure it'd have the expected effect on Happy if that happened. It might kill him or throw his pieces into different dimensions, but it definitely won't have the ideal effect Mard was hoping for. For Zeref, it'd most probably be nothing; for Gray, for whom the Mira and Sayla thing was a nice foreshadowing, it severely injured him (though not that seriously, obviously >.>). As I said, Mard was most probably pissed at the fact that his Curse was incomplete/improperly cast than anything else. *shrugs* People can interpret it as they want, I chose that one. Others are also correct unless Mashima delves further into it ... which I don't think will happen.