In Tales From the Pizzaplex, the Mimic was originally designed to copy David Murray's actions, being playful and occasionally mischievous, such as when David hid inside one of the Fazbear Entertainment character costumes, the animatronic followed suit. After David dies, Edwin beats the Mimic viciously which causes it to learn violence from its own creator. The once infantile, friendly Mimic had been turned into a cold and barbaric killing machine.

The Mimic changes very little from how it appears in RUIN in terms of its personality in Secret of the Mimic. However, it's shown to be capable of holding grudges and displays a capability of being not only sarcastic, but also capable of being extremely petty and venomous. When it caused an explosive accident in Edwin's home office, it began to copy his voice and repeatedly mocked Edwin's helplessness while forcing him to reflect on his neglectful behavior in the past, demonstrating its grudge to its creator. Additionally the Mimic is shown to be sadistic as after the previous event, it makes fun of Edwin even further by talking about the new legs it built for its body.