Mewtwo (SSBU)/Neutral special
Shadow Ball's damage, shield damage, base knockback, and knockback scaling are linearly scaled from the minimum charge hitbox to the maximum charge hitbox for every charge frame. The sound effect's level also changes to M (Medium) when reaching at least half of the move's charge, then to L (Large) at full charge.
The move takes 12 frames to initiate before it can fire or start charging, and can be charge-canceled after this period. The timings listed below are without this initiation period. Charge-canceling also incurs 4 frames of lag before the selected action.
While the Shadow Ball's hitbox is active on frame 4 of release, it often ends up hitting later due to still being inside Mewtwo's jostle area for a few frames.