Wash and dry the celery thoroughly.
Trim the ends and cut the celery into 3–4 inch pieces.
In a medium bowl, combine the shredded chicken, buffalo sauce, softened cream cheese, ranch dressing, and black pepper.
Mix until creamy and evenly combined.
Taste and adjust with additional buffalo sauce or ranch if desired.
Spoon the buffalo chicken mixture into the groove of each celery stick.
Top with sliced green onions and optional crumbled blue cheese.
Drizzle lightly with ranch or buffalo sauce if desired.
Serve immediately or refrigerate until ready to eat.