Similar mobs to turtles in the end dimension

The roamer 

• It is big so the player could jump on them. 
• Roamers inhabit the very lower reaches of the End islands. 
• They fly very very low so that you would only see them when you look down from an island. 
• They spawn medium rare.
• They have a designated homebeach and lay there eggs there. 
• They have a white body with a dark purple shell. 
• Their design and function is similar to the turtles. 
• It purrs when standing on it. 

The turtles are already very well fletched out. I think they can be a good base for this mob. That they fly so low won't change gameplay too much. Gives the player a second chance if they fall of the end islands.