I need help making a AI enemy

umm... many wuestions come to mind, people need to know more about the following:-
What sort of game is it
What do you want the enemy to do
is it 2D or 3D (not so important really)
and I can't really think of any others at the moment

Some more questions or clarifications of Gatz's:
- is it a platform-game or do they move up and down as well as left and right?
- do they move when they attack? Do they shoot?
- Do they start to move when you're close?
- Do they react to your movement, for example: do they duck when you shoot?
- How much do you know about programming in GM? Are you familiar with code, or do you only work with the buttons (D&D)? AI requires code...

If you know code, you could try some things for yourself, using the function "random(maxnumber)". This function returns a random number between 0 and maxnumber. You can make your enemy inpredictable with this function, making his speed, direction and time between attacks random.

thank you trollsplatterer, I didn't realise how vague my wuestions were untill now... must... not... ..sleep...

tollsplatterer is right. we need to know how your enemies attack, how you want them to move, how fast, and at who? c/b cuz i want to help.

well... its a platform game, and they shoot forward, and at a downward angle and they are very slow and it jumps
and at hte main character

Do you know code?

I'd hate spending my time explaining all this to you in code, if your answer would be:
"Thank you, but I don't know anything about code, so I'll try something else."
I could give you some help in D&D, too, but it'd restrict the AI-capabilities of the boogies.

Thank you, but I don't know anything about code, so I'll try something else
there....
and i really dont care if it restricts the AI capabilities... i REALLY dont care

They move towards the main character when you come within 250 pixels and start shooting at a 20 degrees downward angle.
I name the main character-object 'hero', but you have to replace this with the name of the object of your own hero.
These events are to be placed in the enemies:

in the create-event:
- "set variable"-action: variable name: shoot, value: 0


in the step-event:
//test if the hero is closer than 250px, if so, make him move
- "test statement"-action: expression: abs(x - hero.x) < 250
- "start block"-action

//move towards the hero (-1 is left, +1 is right), with a speed between 2 and 5
- "set horizontal speed"-action: hor. speed: (hero.x - x)/abs(hero.x - x) * (2 + random(3))
//enable shooting
- "set variable"-action: variable name: shoot, value: 1

- "end block"-action
- "else"-action
- "start block"-action

// make the enemy stand still and stop the shooting
- "set horizontal speed": 0
- "set variable"-action: variable name: shoot value: 0

- "end block"-action

//if "shoot" is 1, shoot a bullet within 5 seconds, but it can be faster, shoot 20 degrees downwards
- "check expression"-action: expression:
shoot == 1 && random(room_speed*5) == 1
- "create moving"-action: object: badbullet, x:x, y:y, speed: (hero.x - x)/abs(hero.x - x) * 8, direction: -(hero.x - x)/abs(hero.x - x) * 20

I haven't tried it and I hope you understand enough of it to get the bugs out yourself, if there are.
I haven't done the jumping yet.