What is a delta Bakugan?

There's no such thing as a "delta Bakugan" in the Bakugan franchise. Bakugan are creatures with unique attributes, powers, and abilities, but they aren't categorized by Greek letters like "delta."

Perhaps you're thinking of:

* "Delta" as a type of Bakugan attribute: Bakugan have various attributes, such as Pyrus, Aquos, Haos, Ventus, Darkus, and Subterra. There's no "Delta" attribute in the Bakugan universe.

* A specific Bakugan with "Delta" in its name: There might be a specific Bakugan with "Delta" in its name, but it's not a common term used to categorize Bakugan.

* A misspelling or misunderstanding: It's possible you heard or read something incorrectly.

Could you please provide more context or details about what you're looking for? This will help me understand your question better and give you a more accurate answer.