I saw this last week at a tournament and no one seemed to be able to answer this question, so I will put it out for the experts.
P1 attacks low defense face down Spellcaster with a monster with a higher ATK
P2 Flip summons face down Spellcaster in response to the attack
P2 Activates
Magical Dimension to tribute Spellcaster that was just attacked.
Question? Is this a legal move. My initial thought was that it was not as the player tried to activate
Magical Dimension during the Damage Step and as such, the monster was destroyed as a result of the battle and unable to be tributed. But then I thought that he could since
Magical Dimension doesn't have any restrictions on it's activation other than the Spellcaster must be face up, which it was at the time of being flip-summoned. I figured he could chain the activation and effect of
Magical Dimension to the flip-summon of his face-down Spellcaster.
The other question would be- if this is legal and the activating player summons a higher attack Spellcaster and does not destroy the attacking monster, but rather another monster on the field, does the original attack go through?