That’s a decorative wall/ceiling molding accent piece
Based on the material and the long straight trims in the background, this is likely PU foam, polyurethane, or PVC decorative molding.
What it's used for:
It's an ornamental corner piece / applique for interior decoration. Think of it as "jewelry for your walls and ceilings".
Main uses:
1. Ceiling corners - Goes in the corner where crown molding/coving meets. Makes the joint look fancy
2. Wall accents - Mounted on walls as a decorative scroll to break up plain space
3. Panel trim decoration - Center piece for wall panels, wainscoting, or TV wall designs
4. Around doors/windows - As a corner keystone or decorative flourish
5. Furniture / Headboards - Sometimes glued onto cabinets, bed frames, or mirrors for a classic look