You lick me before you put me through the eye

Cereal, Ice cream and Soup all find a home in me before being consumed.

I'm long and green, a garden delight, But some say my shape is a bit impolite. I'm cool in a salad, a refreshing bite, But what am I, causing such lyrical plight?

I start in jars, I end in crumbs, your willpower weakens as hunger comes. A single bite begins the run, what am I that’s never just one?

I'm an unusual mercenary. Some call me a Ninja, but that's one of many labels. I don't charge by the day, You can just buy me once. I have no legs so you need To bring me your victims And drop them into my knives. I'll keep cutting and slashing until you tell me to stop. Pour out the remains into your glass. Yummy!