Ok, well in this thread the question was asked on how to break up players focus firing one target at a time. It seems to have sparked quite the debate as it's up to 16 pages at the time I began this writing.
The OP's gist is basically, all they do is focus fire one mob at a time and I find it boring. This is a fair statement. Some dislike the idea of spreading around damage because it will make combat last longer, and many of these people think combat lasts too long as it is.
I don't have anything against focus firing. After all, if your party finds a good synergistic way to methodically eliminate your enemies, go for it. The quicker you take them down the less of them there are to damage you. Its only good defense by good offense. But like many things, the idea of changing up tactics got my wheels turning.
In the thread there were already mentions of terrain features and things which is good, and something I'll actually explore at a later date. Not so much as traps, or difficult terrain, although that does make a player think, but more along the lines as designing room elements as part of the encounter itself. But as I said, that is for a later date.
Now the following are things that aren't fleshed out, nor are they playtested. These are ideas that can be used as a jumping off point to get your players to do more than "I attack the guy everyone else is attacking." What I am talking about here is creating creatures with abilities that interact in such a way that a party will have to go about combat in a different way to succeed. These aren't so much named powers although powers I will be making and naming, but more like... monster tactic types. For brevity's sake, I will only discuss 3 of them. Because I have thought of many more. Warning... this one is going to be long.
The idea of death rage tactic monsters are that they get stronger as their allies are slain. This can be either offensive or defensive, or both.
The problem with death rage monsters is that if you only have one, and they are the first targeted, they go down as quickly as anything else. However, if you have a lot of them in an encounter the party can quickly become over matched if they don't realize what is happening. The only real numbers that work well are +2 bonus for 5 or more ragers but you can go as high as +5 for a duo of ragers. Using this info you get a sort of inverse bonus depending on how many are allowed in the encounter. 2 per encounter +5, 3 per encounter +4, 4 per encounter +3, 5 or more per encounter +2.
|Creatures per Encounter||2||3||4||5|
You may also want to keep the rage mechanic itself to only apply to other ragers. After all, the stone temple (I nearly typed pilots) guardians don't care how many of the giant bats you slay, only its fellow guardians. Another limiting factor is to type the bonus so they don't stack, or make it an encounter power that can only be used once.
For the example we will use a group of Temple Guardians that gain strength as their numbers are thinned.
|Revenge of the Fallen Guardians ♦ At-Will|
|Trigger (immediate reaction): A temple guardian within 20 squares is reduced to 0 or less hit points.
Effect: The Temple Guardian gains a +2 bonus to attack rolls, damage rolls, and all defenses until the end of the encounter.
The tactic needed to best deal with ragers is to try to take them down evenly to kill them all in the same round in order to not have to deal with the buff.
Adaptive defense is a simple to do monster that makes the players vary up their attacks. This type of creature adapts its physiology in some way to become resistant to the type of damage that it is taking.
A problem with this type of creature is that it can be very book keeping intensive depending on the type of adaptive defense it has. Another issue is that a one trick pony type of character may find that all their attacks are useless against the creature.
The first type of adaptive defense creature is the last hit. These are the easiest to run as there is less book keeping than the other types. These creatures as an immediate reaction to taking damage take on resist (5 per tier) (keywords of the power), or a +2 bonus against certain effects. Each creature can differ on what it gains its defense from as well. For instance if a Paladin starts off with a Terrifying Smite (level 17 encounter) the creature could gain resist 10 radiant; or +2 against powers with the Fear keyword; or both. If the Wizard then follows up with a Combust (level 17 encounter power) the creature loses its radiant resist and gains resist 10 fire.
The next adaptive defense type is the stacking defense. This creature over time builds up an immunity to the attacks against it. The really nasty ones can then unleash the absorbed damage in a blast around it. This type will take a lot more book keeping to keep track of its different resistances, and if there is no way to reset its defenses a character build that focuses on a single energy type can find themselves useless against the creature.
Here is an example of a resisting exploder called an Elemental wisp. Note: Attack bonuses are arbitrary in this case.
|Elemental Tempest (varies) ♦ At-Will|
|Special: This ability must be used when any resistance is equal to or over 20. Its keyword is dependent on the resistance chosen for the attack.
Requirement: You must have a resist to a damage type greater than or equal to 20.
Attack: Close burst 2 (all creatures in burst); +10 vs. Reflex;
Hit: Damage equal to the resistance
Effect: The elemental wisp loses its resistance to that damage type chosen for the attack.
|Elemental Absorption ♦ At-Will|
|Trigger (immediate reaction): The elemental wisp takes damage from an attack.
Effect: The elemental wisp gains resist 5 to the damage type of the attack. If the elemental wisp already has a resistance to that damage type it gains an additional 5 resistance.
The easiest way to deal with this creature is to deal so many different types of damage that it never becomes fully resistant to any of them, or by using smart play the players can use good communications to move away from the creature when it is going to overload. This creature does indeed have a rechargeable power that the PC's themselves charge.
The brood mother is last, but certainly not least. A brood mother works similarly to a rager. While a rager gets stronger as creatures similar to it dies, a brood mother gets stronger as its minions die. The difference is, the brood mother can create more of its minions.
Brood mothers are generally better as elites or solos. The brood mothers themselves should be themselves mostly harmless, but all but impossible to kill. Its minions, however, should be damaging, but very easy to kill.
You generally create a solo brood mother like any other solo. However you also add an additional armor to it based on the number of optimal minions that should be out. So, for example, a level 15 solo brute has defenses of around 27 (15 level + 12 Brute) before ability score adjustments. At this point since it is a paragon tier monster we increase its defenses further by 10, so 37, before stat adjustment. This should make it all but impossible to hit. However, we also give it an aura that weakens it for every minion in its aura. Paragon tier needs 5 minions to equal a single creature. We will have each created minion lower the defenses of the brood mother by 2.
So lets use the start above for a gelatinous spawner. An aberration that is slow (speed 1) and can't do damage on its own unless it can move into a smaller creature's space to absorb it, but can release smaller quicker versions of itself to search for food and for defense. These blobs are able to do more damage (standard level 15 minion damage). If killed they lose form and are absorbed back into the main body. The spawner's normal attack is to create a spawnling. It has a rechargeable (6) power that allows it to create 5 spawnlings at once. It then has this aura.
|Lowered Integrity ♦ Aura 40|
|Effect: Takes a -2 penalty to all defenses for each spawning in the aura.|
Now the players have a choice, they can keep the minions cleaned up at all times and do nearly no damage to the spawner, they can allow the optimal amount of spawnlings live in order to do normal damage to the spawner, or they can speed up the process by letting out many spawnlings lowering the defenses of the spawnling.
Alternately, you can keep defenses the same and give the mob resist all 25. You then give the brood mother a stacking vulnerability 5 for each spawnling in the aura.
Whew... As I said in my warning, a bit long on this one.
Now I don't suggest you use this for every fight. These are for that once in a blue moon fight when things are just right for a change of pace. Using these over and over will just mean your players will come up with a tactic for it and you are right back at square one.
I hope you enjoyed reading this as much as I enjoyed brainstorming about it and coming up with these few examples.