The Ladybug
Resized to 46% of original (view original)
Artist's commentary
Air Groove Who Loves the Ladybug
Umamusume × Car Series #6
Air Groove × Subaru 360 (The Ladybug)
That's how I interpreted "Air Groove's Secret".
Umamusume character trivia info. Though the original was probably intended to mean Air Groove likes the ladybug beetle.