Chibi Bull Pixel Combo Sprite Sheet

Goal: Create a pixel-art sprite sheet for a looping fighting-game combo animation featuring a cute chibi bull mascot named Niulai.
Canvas: Square sprite sheet on a pure black background, arranged as exactly 16 evenly spaced frames in a 4 columns by 4 rows grid. No frame borders, no labels, no UI, no text. Each sprite should be centered in its cell with consistent scale, leaving generous black spacing between frames.
Character design: A small rounded chibi bull with a bright golden yellow-orange body, oversized head, short limbs, clenched fists, dark gray curved horns, orange pointed ears, pale pink muzzle, small rectangular black eyes, cream hooves, and a thin tail ending in a dark tuft. Give it a determined but cute fighting expression. Use crisp retro game pixel art with visible square pixels, soft 2D shading, black/dark outline, and slight glow on impact effects.
Frame sequence: Show exactly 16 discrete sprites, ordered left to right, top to bottom, forming one smooth loop.
1. Front-facing idle stance, fists raised near chest, eyes open.
2. Same idle stance, eyes closed in a blink.
3. Slight side-facing guard stance, body angled right, one fist chambered.
4. Side-facing wind-up, right fist beginning to extend.
5. Left straight punch fully extended, yellow speed streaks trailing behind the fist.
6. Second straight punch with stronger horizontal motion blur behind the arm.
7. Right punch with a bright yellow crescent slash arc sweeping upward in front of the fist.
8. Punch impact frame with a sharp yellow-white starburst explosion at the fist.
9. Knee lift preparation, one knee raised high, fists guarded.
10. High side kick, leg extended horizontally, yellow curved light blade trailing from the kick.
11. Back-facing spinning kick, body turned away, leg extended left, yellow crescent arc sweeping across the back.
12. Ground slam, bull crouched low on all fours, head forward, yellow-white sparks and impact lines bursting from the ground.
13. Low crouch recovery, one hand near the floor, tail visible, expression focused.
14. Return to front-facing guard stance, fists raised.
15. Idle stance again, centered and stable.
16. Final idle blink frame, eyes closed, ready to loop seamlessly back to frame 1.
Visual style: 16-bit pixel art game sprite, clean readable silhouettes, saturated colors, minimal background, dynamic arcade fighting animation effects in yellow and white. Keep every frame as a separate static sprite pose, not a motion blur composite except where specified.
Constraints: exactly 16 bull sprites, exactly 4 by 4 grid, black background only, no captions or numbers, no extra characters, no watermark, no cropping, consistent character proportions across all frames.