Sokenzan, Crucible of Defiance

{T}: Add {R}.
Channel — {3}{R}, Discard this card: Create two 1/1 colorless Spirit creature tokens. They gain haste until end of turn. This ability costs {1} less to activate for each legendary creature you control.

Magic Online Promos

Kamigawa: Neon Dynasty

Kamigawa: Neon Dynasty Promos

Discarding the card is part of the cost to activate a channel ability.

If a channel ability requires a target, you may not activate it without a target just to discard the card.