What is the green thing in sushi?

The green thing in sushi is typically either avocado, cucumber, or shiso leaf.

Avocado: Avocado is a green, buttery fruit that is often used in sushi rolls. It has a mild flavor and a creamy texture that pairs well with other sushi ingredients.

Cucumber: Cucumber is a green, crunchy vegetable that is also often used in sushi rolls. It has a refreshing flavor and a crisp texture that adds contrast to other sushi ingredients.

Shiso leaf: Shiso leaf is a green, aromatic leaf that is sometimes used in sushi rolls. It has a slightly pungent flavor and a slightly chewy texture that can add a unique flavor to sushi.