Hop straight down from the spawn point and the grate, then an Octoling will jump from the center. Taking it out will make it easier to reach the next checkpoint. Follow the line of Power Eggs and you have reached Checkpoint 1.
Checkpoint 1
Follow the line of Power Eggs to the center and another Octoling will come. Again, splatting it will make reaching the checkpoint much easier. You will be confronted by another Octoling, so do the same as before. Follow the trail of Power Eggs round and you will reach Checkpoint 2.
Checkpoint 2
Follow the Power Eggs round to find another Octoling and splat it. There is another path of Power Eggs - follow it and you have reached the final checkpoint.
Final Checkpoint
There is a trail of Power Eggs. Follow them around and an Octoling will try to ambush you from behind a potted plant. Then, climb the Inkrail up to the part you cannot usually reach and you will find another Octoling. Splat it, then climb the Inkrail to the grate and you have reached the Zapfish.
Location: Hidden under a ramp, along the western side of the level. Go through the level as normal and reach the Zapfish. In its corner facing the rest of the level, head to the closest ramp on the path to the right. Go around the back of it to find the scroll.
The Italian name for the stage contains a pun on serrato (tight, fierce) and serra (dome).
If an Octoling touches the Zapfish after the barrier has been destroyed, the level is completed as if the player has touched it. This is because the Octolings are considered the same as Inklings by the game. However, due to the logistics of this, it can only be performed during this level, by prematurely destroying the barrier with the Inkzooka or the Splat Bomb.[1][2]
Zapfish is back there!
, and then blow 'em down with 
!
