I was wondering how Reverse Trap effects Megamorph. Does the monster's attack halve, or does Reverse Trap have no effect?

(I hope I'm not breaching any rules by posting this...)

Reverse Trap will have no effect.

Reverse Trap does not affect cards which double or halve the ATK or DEF of a monster, such as Megamorph. It only affects changes that are a specific amount (e.g., ALO's +200 boost).

Reverse Trap does not work on cards that "double" or "halve" the ATK/DEF of monster's

It also does not work on cards that "reduce the ATK/DEF to 0," or to a specific amount, like Cat's Ear Tribe.

It must be a specific increase like Axe of Despair raises by 1000 points or Black Pendant raises by 500 or Dark Jeroid lowers by 800, etc.

Thank you very much, I appreciate your help and I'm glad I know the rule now.