A marching band baritone saxophone (bari sax) player typically has a distinct and memorable look due to the size of the instrument and the energy they bring. Here’s a description of their appearance:

1. **Instrument size**: The bari sax is one of the largest and heaviest instruments in the marching band, so the player is often seen with the sax draped over their shoulder with a neck strap or harness for support. The instrument itself is large, with a curved neck and wide bell, making it a prominent visual element.

2. **Posture**: Due to the weight and size of the bari sax, the player’s posture is generally more grounded. They stand with a wide stance to maintain balance and stability while marching. Their upper body leans slightly to one side to accommodate the instrument’s weight.

3. **Marching uniform**: Like the rest of the marching band, the bari sax player wears a traditional uniform, often consisting of a high-collared jacket, fitted pants, tall shako hat (with a plume), and gloves. These uniforms tend to be elaborate, often featuring the school or band colors and insignia.

4. **Attitude and vibe**: Bari sax players are known for being cool and confident, often having a laid-back but charismatic presence in the band. Because they play such a deep, powerful instrument, they tend to exude a subtle confidence, and you might see them casually nodding their heads or swaying slightly with the beat when they're not marching.

5. **Mouthpiece and embouchure**: While playing, their embouchure is focused but relaxed to manage the deep, rich tones of the instrument. Since the mouthpiece of the bari sax is larger than that of other saxophones, it gives the player a slightly different facial posture — their lips and cheeks need to accommodate more space while maintaining control of their airflow.

6. **Movement and coordination**: Due to the size of the bari sax, the player has to be extra coordinated while marching. Their movements are smooth and calculated, with exaggerated leg strides to match the precision of the rest of the band while keeping the instrument in control.

Overall, a marching band bari sax player cuts an impressive figure, blending strength, coordination, and a cool, confident demeanor that matches the deep, resonant sound they produce.