Command Link: http://pastebin.com/mhvUBeh2
WARNING:
1# Only click the signs once or the machine will stop working.
2# Before you copy and paste it into a command block make sure you replace the command: Owner:Babam456 With: [Owner:YourUsername]
3# If You want to change the pet than scroll through the command until you get to: /summon VillagerGolem Then replace VillagerGolem with the entity's name