>>52917392It does have the highest functional SpAtk stat in the game.
Base 135, fully invested, with the Beads of Ruin boost, is the equivalent of base 197. Higher than Mega Mewtwo Y.
So by that metric, it's the strongest of all time.
There are mons with a higher offensive stat functionally, like Mega Mawile (functionally 268 base Attack) and Zacian-C (functionally 279 base Attack) but they both need to hold items while Chi-Yu can hold Specs freely.
But in terms of damage output, it's not exactly the strongest. Miraidon, assuming it's in Electric Terrain, can do more damage with Thunder than Chi-Yu can do with Overheat. Out of sun.
>252+ SpA Choice Specs Hadron Engine Miraidon Thunder vs. 0 HP / 0 SpD Mew in Electric Terrain: 526-621 (154.2 - 182.1%) -- guaranteed OHKO>252+ SpA Choice Specs Beads of Ruin Chi-Yu Overheat vs. 0 HP / 0 SpD Mew: 478-564 (140.1 - 165.3%) -- guaranteed OHKOSame goes for Kyogre's full-HP Water Spout in the rain
>252+ SpA Choice Specs Kyogre Water Spout (150 BP) vs. 0 HP / 0 SpD Mew in Rain: 672-792 (197 - 232.2%) -- guaranteed OHKOHowever, in the sun, it outdoes them both.
>252+ SpA Choice Specs Beads of Ruin Chi-Yu Overheat vs. 0 HP / 0 SpD Mew in Sun: 718-846 (210.5 - 248%) -- guaranteed OHKOBut since Chi-Yu can't set its own sun, you might not want to count that.
