Growing up with a series also means realizing that its characters couldn’t stay little forever.
In Rugrats, Spike accompanied Tommy from his earliest adventures and ended up becoming much more than the family pet: he was his companion, his protector, and a constant presence while everything around him changed.
That’s why, when All Grown Up! showed Tommy and the rest of the group as teenagers, it also revealed something much quieter and more painful: Spike had grown old.
The series never needed to turn it into a major drama. It was enough to see him older to understand that time had passed for him too, and that even pets who seem eternal during childhood eventually grow old.
For many, seeing Spike as an old dog was one of those details that seemed small but suddenly reminded them that growing up also means learning to say goodbye.