Forum:Gravekeeper's Chief and Book of Moon

Okay. I was playing Yu-Gi-Oh! 5D's Duel Transer and I Tribute Summoned a Gravekeeper's Chief. I activated its effect to Special Summon one Gravekeeper's monster from the Graveyard and my opponent chains with Book of Moon. For some reason, when my Gravekeeper's Chief got flipped facedown, the effect got negated.

Is this a glitch or is there a specific ruling for this? Mark Mares (talk • contribs) 02:27, January 16, 2011 (UTC)