NPC Infecter SWEP

Are there any facepunchers out there who know how to use lua really well? I want to request a gun that turns any human npc into a zombie.

Weapon Model= HL2 Pistol
Weapon Sound= HL2 Crossbow
Weapon Effect= AR2 Primary Fire muzzle Effect
Weapon Purpose= Turns human NPCs into zombies

If this is possible, when a human npc gets shot with this weapon, it acts like it dies. The npc falls over, but it is really just unconscious. I want it after 5 seconds, the NPC’s body turns into a zombie model, then uses the zombie “prone” animation.

So the zombie gets up with the “prone” animation as it gets up.

Please reply, lua coders. Thank you.