Can the Trap card Disappear remove 1 of the monsters your opponent selects to summon chaos sorcerer or megarock dragon etc?


I think the answer is no, but I would like a techincal answer explaining why.

No, simply because removing monsters for Chaos Sorcerer, Megarock Dragon, etc. is NOT an effect, it is a cost for those monsters to be able to be special summoned.

Yep..and costs are paid BEFORE the time you could actually chain anything (also because you can't chain to a summon).

You can however, use Disappear against effects that trigger in the Grave...like say, Phoenix, Dark World, Vampire Lord, and Treeborn Frog, to remove them before they are special summoned.