Oozora Subaru's "3D" model. Thanks to her hilariously bad attempts at ASMR, she has been compared to Donald Duck and then, ducks in general. Thus, in this form, she appears as a white duck with her signature baseball cap. Might or might not be randomly tumbling and changing sizes.
The duck later became her own channel mascot. It speaks using Subaru's ASMR duck voice.