Forum:Gallis the Star Beast

Scenario: I have a Fossil Dyna Pachycephalo or one of the Barrier Statues on the field. I also have a Gallis the Star Beast in hand. Finally, there are only monsters in my deck... no spells or traps.

Given this scenario, would I be able to activate Gallis the Star Beast's effect to send the top card (obviously, a monster), then do damage equal to the monsters level, then keep Gallis the Star Beast in hand because he is unable to be special summoned to the field? (Thus creating an effective one turn kill where I send the top card to graveyard, deal damage, then rinse and repeat for as long as I still have cards in my deck)

According to the OCG rulings page, referring to the same scenario but with Scapegoat, it says you cannot. However, I have had a few judges who ruled to the contrary.

In the ruling for Black Garden you are still able to activate Black Garden's effect to halve a monster's attack even though you cannot special summon a monster to the field because of no open monster zones or Fossil Dyna Pachycephalo's effect, et al. However, in the ruling for Magical Dimension, you are not allowed to activate Magical Dimension if you do not have a Spellcaster type monster in your hand!!

So, in the end, I am a little confused. The Black Garden ruling says my combo works, but the Magical Dimension ruling says the combo doesn't work... Is there a difference between the two because Black Garden is a triggered effect, or is one the rulings incorrect?