Sem's little zombie apocalypse

A interesting spin of the Fungal spore mod mixed with the TACZ Expanded Mods (gunmods) with a prebuild world "Mosslorn" an 1000x1000 Abandoned Overgrown City by Milkshake_mp3 with storyline (Optional) or just pure survival.

Not made for outside of the prebuilt Mosslorn but you can try

Fungal Spore mod discription (taken from them) 

• As you start your world, you'll find infected humans emerge, ready to spread the infection. Their bite inflicts Mycelium Infection, and upon a suitable host falling, they will rise again, as a pawn of the infection. This... thing is a bioweapon, built to eradiate mankind, and will only infect other humans.
• Mutation: As the horrific infecteds eat and consume more biomass, they'll begin to undergo an evolution, mutating into new stronger forms, with the sole goal of elimination... and the reconstruction of a fallen hivemind.
• The Hivemind: The infection wishes, beyond the culling of mankind, to rebuilt their hivemind. They have improved A.I. compared to vanilla mobs, and will attempt to group up into hordes, request back-up, build a hierarchy, and even begin the reconstruction of the hivemind, an interconnected network of minds. Be prepared, for as the infection begins to take root in this peaceful Minecraft world, you might just encounter horrific constructs of fallen humans, constructed by the contorted minds of their fallen brethren.