How to change the skin of Zombies in Minecraft 1.7.2?

My mom said i can't play minecraft because of the zombies… But if i could make them look like bears or something i would be aloud o play minecraft! So please help me. And No i'm not going to place torches around minecraft OR turning it on peacefu… Peacefuls Way to easy. Also I can change files inside the finder and stuff. So if i have to go and mod minecraft i can to a point.

Added (1). Well zachary I have had nightmares about zombies… Thats why she won't let me play it… And I tried replacing the zombie skin it doesn't work

Well you can go to a minecraft skin website or make your own skin and replace it with the zombie skin in.minecraft. But hopefully your Really young for your mom to not let you play with zombies they don't even really look like zombies, you should show her skeletons and endermen (You might have to replace every mob texture, No offense it just seems Over dramatic)

Change zombie texture.

Download a texture pack/resource.

Tell your mom that they are not zombies but simply just fabulous gentlemen that want to meet you and are just wearing non-toxic super-safe organic face paint that can be used by anybody age 3 and above. And to demonstrate that just go into creative mode and tell her that as the zombies won't attack. In an emergeny situation where your mom plays minecraft too, get a different texture pack or just switch to peaceful mode, that way, no hostile mobs (the things that attack you or blow up in your face) will be there and you will not see them there. Also, peaceful mode will prevent you from wetting your blankie when you get nightmares of a very unrealistic cube-cuboid shaped zombie eating your brain and your flesh out