The vampire is my favorite of the examples.  Vampire throws jump
instructions around in memory (I call them "FANGS").  If one of the
fangs happens to land in the enemy program then the enemy will jump
into a trap.  The trap creates several hundred new programs which do
nothing but jump to themselves.  This of course robbs the enemy of
almost all his effective power.  Any other programs that he might
have running will be going so slow as to be almost harmless.  When
vampire detects that one of its fangs has found a jugular, it begins
a methodical erasure of memory.  If all goes well, all the enemies
programs will be erased, and VAMPIRE will win.

*
* Vampire -- seek out the enemy, drain the life out of him/her, and then
* erase him/her in his/her weakened condition.
*
@-230
nprc 	dat 500
* the number of dummy processes that the enemy will be forced to make
spin	spl 0
	djz 2 nprc
trap	jmp -1
*
	mov null trap
	mov #0 spin
null	jmp 0
@-2
fang	jmp @1
bite	dat 1000
@0
start	mov #(spin-bite) @bite
	sub bite @bite
	sub #1 bite
        mov fang @bite
	add #10 bite
	*
	cmp #500 nprc 	* have we caught anybody?
	jmp start	* nope.
*
* the enemy has been caught, and is currently being drained of energy. So 
* start the process of erasing the world.
*
	mov #100 bite	* start near here
erase	mov #0 @bite	* erase everything and	
	add #1 bite	* hope he dies before we kill ourselves
	jmp erase