A Dynamaxed Lucario (transformed from a Throh) did 2% damage with Max Lightning (Power: 90) to a Wailord in Hackmons Cup.
On Hackmons Cup moves, abilities, IVs... (almost) everything is random.
Lucario had Battle Armor and a berry.
Wailord had no useful ability or item.
Base move for Max Lightning (Power: 90) was Max Lightning (Power: 10). Electric Terrain was not active yet when Max Lightning was used.
My Throh transformed into a Lucario with +Speed and +1 Atk, got Dynamaxed, fainted the opposing Lucario with Max Flare (base move Flame Charge) and the enemy switched their Wailord. Throh (now a Dynamaxed Lucario) used Max Lightning (Power: 90) against the Wailord, which had setup Shell Trap.
Both me and my opponent think this is a bug.
Screenshot:
View attachment 241846
Please check the replay here:
https://replay.pokemonshowdown.com/gen8hackmonscup-1107116412