Spike is a central character in Hasbro's My Little Pony franchise, primarily known from My Little Pony: Friendship Is Magic. He is depicted as an anthropomorphic baby dragon, adopted younger brother, and loyal assistant to the main protagonist, Twilight Sparkle. Spike's duties include organizing Twilight's activities, taking notes, and magically sending letters via his fire breath. He also harbors an unrequited affection for the character Rarity and possesses a strong appetite for gems. Throughout the series, Spike experiences personal growth, facing challenges related to his dragon identity and his place among ponies. He plays heroic roles, such as aiding in the defense of the Crystal Empire, and eventually becomes Equestria's friendship ambassador to the dragons. His character development includes gaining wings and becoming Twilight's royal advisor.

Beyond the main series, Spike appears in various spin-offs and related media, including the Equestria Girls films where he often transforms into a talking dog and assists Twilight in the human world. In the Pony Life reboot, he is a secondary character with wings from the start, and in Make Your Mark, he is a grown dragon and the new Dragon Lord. Critical analyses have explored Spike's characterization, noting his role as a male supporting character, his struggles with gender stereotypes, and his portrayal as an indentured servant. These discussions highlight themes of identity, belonging, and the complex dynamics within the series' narrative.

A recurring theme in Spike's narrative arc is his struggle to reconcile his identity as a dragon with his life among ponies. This journey of self-discovery is explored in various episodes, highlighting his efforts to understand his role and place in the world beyond his function as Twilight Sparkle's assistant. His interactions with other dragons, particularly Princess Ember, who becomes the ruler of the Dragon Lands, are pivotal. These encounters help him forge a connection with his draconic heritage and eventually lead to his appointment as Equestria's official friendship ambassador to the dragons. This role signifies a bridge-building between two distinct cultures and emphasizes his unique position as an intermediary.

Spike's relationships are a key element of his character. His primary bond is with Twilight Sparkle, his adoptive sister and mentor, for whom he serves as a devoted assistant. He also experiences an unrequited crush on Rarity, which often leads to comedic and sometimes problematic situations, as analyzed by critics. His interactions with Twilight's friends further define his social landscape. As the only male member of the core group, his perspective and experiences offer a distinct dynamic. His role as a foil to the main characters, differing in personality, size, and species, provides opportunities for exploring themes of difference and acceptance within the series.

Scholarly and critical analyses have examined Spike's characterization from various angles. Some scholars have pointed to his role as a male character in a predominantly female-led series, often positioned in a secondary or subservient capacity. His dialogue and duties have been described as often short and comedic, placing him socially beneath the female protagonists. Furthermore, his character has been criticized for exhibiting "Nice Guy Syndrome" and problematic gender essentialism, particularly in early episodes. The portrayal of Spike as an indentured servant, performing chores and sleeping in a dog bed despite his sapience, has also drawn criticism, with comparisons made to themes of adoption and savior narratives.