[Requirement] Send the top card of your Deck to the Graveyard.
[Effect] Choose 1 face-up Normal Monster (1000 ATK or less) on your field, it gains 1000 ATK until the end of this turn.
“Senkou” here is a pun. It’s likely based on a different “senkou” (線香), which is the type of firework that cover sparklers (used by the man in the background). These are common during the Obon Festival, along with the cucumber horse and eggplant cow, and are related to the visiting and departure of spirits.
Here, “senkou” has been replaced by 千攻, which are “1000” and “Attack” mashed together. Essentially, a super oversized firework to celebrate the occasion.