Xantid Swarm

[Maxpayne03]

If I attack with {Xantid Swarm}, then I cast {Chain of Vapor}, can my opponent sac a land to copy vapor?

[Sparkle Ninja]

Yes. The chain vapor states that they are making a copy and therefore does not count as being cast

[Prplprince]

Also the "mays" will enter the stack above the silence ability