Magic Cylinder

[Knightmare88]

If I use Geomathmech Final Sigma and attack my opponent's monster, and they activate Magic Cylinder in response to my attack, do I take damage equal to double Geomathmech Final Sigma's attack because it deals double damage when attacking a monster, or do I only take damage equal to Geomathmech Final Sigma's attack?

[chaseer]

No. Magic Cylinder deals damage equal to the attacking monster’s current ATK. Sigma’s double battle damage has no iteration with Magic Cylinder. I think you're confused with the other card (Dimension Wall)

[greg503]

This assumes, of course, that Final Sigma is not in the EMZ and can be affected by non-mathmech cards

[Shugunou]

Yes, Magic Cylinder inflicts effect damage, not battle damage, so an effect that doubles battle damage like Final Sigma does not impact the damage taken.