I designed and animated a system of avatar interactions, including locomotion, reactive clothing behaviors, emotion-driven poses, and expressive sticker moments, that translated user research and trend insights into tangible micro-interactions. I made specific interaction decisions such as calibrating pose timing and hold duration so each sticker read instantly as a reaction, and mapping how the avatar responded differently across trigger states (idle, emotion change, clothing swap) to keep behavior consistent and legible. Working cross-functionally with UX researchers, artists, and engineers, I built interaction prototypes from low-fidelity blocking to high-fidelity motion, and iterated through multiple rounds of internal usability testing, refining timing, exaggeration, and readability until the interactions felt intuitive and delightful. One sticker in particular used humor as an interaction hook, becoming a standout example of the approach and resonating strongly with users.