You cannot activate “Ojama Trio” if there are not 3 vacant Monster Zones on your opponent’s side of the field.
You cannot activate “Ojama Trio” if “Scapegoat” or “The Last Warrior from Another Planet” is preventing you from Summoning.
If there are Ojama Tokens on your opponent’s side of the field, and “Remove Brainwashing” is activated, the Ojama Tokens are switched to your side of the field. If you don’t have enough Monster Zones for them, some of the Ojama Tokens are destroyed and the damage is inflicted to the opponent.
When you chain Ojama Trio to your opponent’s “Call of the Mummy” effect, the effect of “Call of the Mummy” is negated.
When your opponent activates “Snatch Steal”, and you chain “Ojama Trio” to fill up his/her remaining Monster Zones, then there is no room for the stolen monster, and it is destroyed.
Netrep Rulings:
The opponent must have 3 open Monster Spaces to activate “Ojama Trio.”
If the opponent does not have 3 open Monster Spaces at the resolution of “Ojama Trio,” the effect of “Ojama Trio” disappears.
Damage is inflicted by the effect of “Ojama Trio” only when the Ojama Tokens are destroyed.
If “Remove Brainwashing” is active while Ojama tokens are on the field, the Ojama tokens will change to the side of the field of the player who activated “Ojama Trio.”
Netrep Q&As:
Q: Can you chain “Ojama Trio” to the activation of a Spell or Trap Card that would Special Summon a monster in order to fill your opponents Monster Card Zone and prevent the Special Summon of the monster?
A: If there is no open Monster Zone spaces during the resolution of the card that will Special Summon the monster, the monster is destroyed. In some cases like “Polymerization,” one of the monsters on your opponent’s side of the field may be used in the Fusion and would then leave an open space. Your opponent performing a Ritual Summon might offer a monster on their side of the field as a Tribute and would then have an open Monster Zone space to Special Summon the Ritual Monster. (They might even use your “Ojama Tokens” to help pay for the Ritual, since this Tribute would not be for a Tribute Summon) It can be situational. Curtis Schultz, 01/13/2004