As the question says, really.
Will toxic trigger the switch from shield to blade forme?
No, Toxic will not cause Aegislash to change to Blade form as it is a status move and not an attacking move. Only moves that deal damage directly will cause Aegislash to change to Blade form; moves like Toxic that cause status conditions and moves that effect stats will not change Aegislash's form (unless they deal damage, like Power-Up Punch which deals damage and increases Attack by 1 stage).
