Can I activate Super Mega Death Rocket's ability to add it to my hand if I have no cards to discard?

Ruling: No, you cannot activate Super Mega Death Rocket's ability if you have no cards to discard. The "discard to" wording indicates that discarding is a cost that must be paid when the ability resolves.

Nuances:

• The key distinction is "discard TO" versus "discard THEN" - the "to" wording makes it a cost that must be paid
• You can still add the ability to the chain at 0 cards (e.g., stacking it with other effects), but when it resolves, if you cannot discard a card, you cannot recover the Death Rocket to hand
• If it said "discard then" instead, you would not be required to discard if you had no cards