this is by ristar but i copy it to questions

-Question:
"Discard to the graveyard" and "Send to the graveyard" vs Macro Cosmos.
When paying costs, sending to the graveyard is not possible while Macro Cosmos is on field. But is discarding possible? Discard != Send.

-Answer:
The key part is "...to the Graveyard", not whether it is sent or discarded. If it is a cost and the requirement is for the card to reach the Graveyard (by whatever means) that cost can not be paid whilst Macro Cosmos is on the field. Cards like Snipe Hunter simply say "Discard" and don't care where the card ends up, so these can have the cost paid while Macro is on the field.


Actual cards that don't work in these conditions:

Card Trooper
D.D. Crow
Darklord Zerato
Electric Virus / Puppet Plant / Marionette Mite
Elemental Hero Captain Gold / GK Commandant
Honest
King of the Swamp
Prime Material Dragon
Rescue Cat
Ancient City - Rainbow Ruins (3rd effect)
Wave-Motion Cannon
Six Samurai United
Spell Reproduction