Can you list each of your problems, one by one, providing all the relevant code?

Kolie wrote:

ob

Well firstly, this should be mob, not ob, but I'm assuming you accidentally deleted the m when posting this.

icon = 'person.dmi' //make it so all mobs will be created with the person icon

bug //new prototype
icon = 'bug.dmi'

var
HP = 30 //define a new variable called HP, with a value of 30
wealth

Login()
icon_state = gender //when a player logs in, get them the right icon state for
..() //the gender of their key. Then call the parent!

proc

DeathCheck()
if (HP <= 0)
world << "[src] dies!"
<font color=white>del src</font>

No wonder it doesn't disappear... you're not telling it to! Add the highlighted line to delete the monster when it dies.

verb
attack(mob/M as mob in oview(1))
usr << "You attack [M]!"
oview() << "[usr] attacks [M]!"

The above line wasn't complete; I've finished it off for you, in the assumption that again, you accidentally deleted a bit of it while posting.

var/damage = rand(1,10)
world << "[damage] damage!"
M:HP -= damage
M:DeathCheck()

Don't use the : operator here, use the . operator. All the : operator does is assume that the var/proc exists, whether it does or not. Therefore you won't get any compiler warnings about it, and you could potentially get nasty runtime errors. Better safe than sorry.

obj

bug
icon = 'bug.dmi'

Why are you defining /obj/bug? You've already defined a bug (/mob/bug), so you shouldn't need

gold //define a "gold" prototype, which is a kind of obj
icon = 'gold.dmi' //set the default icon
var
amount //declare a new variable called "amount"

verb
get() //obj/gold/verb/get()
set src in view(1) //src must be close
usr << "You pick up [amount] gold."
usr.wealth += amount //add to usr.wealth
del(src) //delete the gold

Del()
var/obj/gold/G = new(loc) //create a new obj from the gold blueprint
G.amount = rand(1,100) //set its amount variable randomly
..()

This is why the monsters won't drop gold; you've programmed all objs to drop gold rather than the monsters, which are mobs, not objs. :-) Move everything under obj/Del() to mob/proc/DeathCheck(), making DeathCheck() look like so:

proc

DeathCheck()
if (HP <= 0)
world << "[src] dies!"
var/obj/gold/G = new(loc) //create a new obj from the gold blueprint
G.amount = rand(1,100) //set its amount variable randomly
del src //You must put del src last, because deleting src will terminate the procedure. If you put it before your gold dropping code, the gold will never get dropped.

As for making monsters move around and attack you, that's a little more complex - although certainly not much harder than what you've been doing already. Look up spawn(), sleep(), step_to(), and walk_to() to work out how to make monsters follow you around; then just call your attack verb (verbs are really just procs with extra features) to make the monsters attack the player when they're next to them.