How can i made a Teameable Pet Entity

when right click on the entities check if there are cookie in player inventory check if not in creative then remove 1 cookie,replace the entity with the tamable version and create particle 

I don't know why it not show the image but here the link https://imagebin.ca/v/5IBMMeqNeVfb

i want to make minecraft foxes dont scream and be tameable and not scared and you can make them sit to not attack other entityes