When Luca's parents, Daniela and Lorenzo, arrive on dry land to find their son, they quickly realize that walking around in woven kelp might be a bit conspicuous.
Later, when Massimo notices that Alberto is staring at his sleeve, he answers the question that Alberto is obviously wondering about, saying that a sea monster ate his arm.
Sitting on the floor at the foot of her bed is a small plush of Donald Duck.
When Luca arrives home an entire two minutes late, his mother asks about his tardiness, asking if there was a boat that forced him to hide until it passed.
Similar to the hidden Mickeys is another familiar face that can be seen plainly in Giulia's room as she shows Luca her books.
These types of feelings are referred to as phantom sensations.
When Luca gets out of the water and goes through his human transformation for the first time, he immediately notices that his new body lacks a tail.
Some of the references are small, such as a street sign in the background where Alberto and Luca first ask Giulia about the race.