Activate Megatog by sacrificing Sword of the Meek.
Skittering Precursor triggers, creating a 0/1 Eldrazi Spawn creature token.
When the Eldrazi Spawn enters the battlefield as a 1/1 due to Judith, Sword of the Meek triggers, returning Sword of the Meek from your graveyard to the battlefield attached to the Eldrazi Spawn.
Resolve the Megatog ability, giving it +3/+3 until end of turn.