Hey so about a week ago me and a few other people did a creeper, a snake, and a water survival i know how to do the water survival but i dont know how to do the creepers or snakes can someone tell me how, i know how to make the creeper bot chase u and kill u but  i checked and they were not bots and they were just black block over tnt block and they blew up?

you can cange the texture of them and you have /zombie 

how do i change the texture can i make ther /creeper look like a creeper?

 

You need to know where the texture of the /creeper come from to be able to modify it.
It may be terrain.png

You know /lb command.If yes just cange the texture of the lime wool and TNT