Make mob attack other of it's kimd

Make another mob with the same model/texture that attacks the other kind and/or it's own kind. People wont tell the difference between them and it makes it look random :)

after you create the mob element, mcreator will have it in a drop down list of entities you can choose from in certain code blocks. so go back into you mob's AI page and use block "attack entities of type [...]" and select your mob in that dropdown list

He/she said that he/she wanted it to occasionally attack. Not always attack.