Interesting Boss/Encounter Mechanics

Hello, I am fairy new to GMing and I've been running a basic D20(I think it's called GURPS) based campaign.

Since most of the rules,skills I've made up myself I dont have much reference when creating NPCs or Scenarios.

Any suggestions for interesting Boss or enemy mechanics that I can utilize?

Things like:
-Must kill adds before boss
-Shield that's is generated somehow
-Only hit by certain types of attacks

Trying to make combat more interesting than spawning enemies and waiting for the group to kill them without thinking.

You can always incorporate environmental factors into the fight. Be it a big firepit, a geyser shooting steaming water, a poison cloud or lasers flying about a mad scientists lab. Give them a separate turn on the initiative roster.

Another alternative is to have multiple statlines for the Boss, and use each one for a different 'phase' of the fight. So as the boss gets beaten down he gets more desperate and stops casting magic and becomes more frantic, wielding a giant blade and trying to cleave the heroes apart, with different stats to represent that.

Ahhhhh. I never thought about incorporating environmental hazards. I like it.

gb2 Arcadia

Most boss mechanics are really just variants on what's already been posted. You just add nuance and clarification to it, maybe in a different phase the boss is weaker to fire attacks and in another he dons a suit of plate armour and electricity harms him more. WHen he's changing he summons minions and underlings who clad him in armour while others try to stall you etc

make them only able to beat him by using the left half of their brain

okay , now seriously.
>the adventurer must find out the "true" name of the foe to be able to deal sufficient damage
>the boss is distracted by certain objects , such as gold coins
>resistance against certain attack types such as stabbing (skeketons)
>they have protective mechanisms such as corrosive juices. a player of mine did wrap a leather cloth around his sword so he could bludgeon a slime to death without wrecking his weapon
>i once noted character traits based on the roleplaying. most players were marked with greed due to their behavior. i had them fight against a greed demon , which used cursed coins to distract enemies. those who were marked with greed had to make the WIL check twice , and taking the lower check which made them almost completely helpless.

and most important , give an intelligent encounter the same tactical capabilities as the PCs. nothing is more annoying than an enemy which can actually think of ways to kill the party.

Boss is a gelatinous cube

But after so much damage has been dealt, enough of the cube has been hacked away that the skeleton trapped inside is capable of pulling free and attacks the party. And then another skeleton after so much more damage has been dealt, and another, and another.

Boss can only be damaged while a PC is holding down a lever and/or plate. This requires both hands and the PC's full attention, meaning they can't attack or defend themselves

I appreciate the help. Simple stuff like this I need to write down. I always randomly think of these things, but never write them down

>I've been running a basic D20(I think it's called GURPS)
wat

time limits/conditions are always fun.
>boss took a potion, in 3 turns he'll double damage
>spiked walls are closing in, you have 6 turns to kill everything or you die
>two bosses each trying to execute a prisoner at the same time, if you can't kill one fast enough to get to the second in time then second prisoner will die

environment is also great, my favorite fight I've been in went like this
>mad scientist living in a treehouse 100ft off the ground
>was questgiver, we got tricked into bringing him the macguffin
>he has a servant put it in a machine 2 floors above us, turns him into the hulk
>realize we fucked up
>monk dashes up stairs to turn off machine
>hulk tries to follow, we have to distract him
>hulk knocking us out onto balcony
>balcony crumbling
>hulk knocks warlock off, warlock barely holding onto edge which is crumbling
>fighter tackles hulk off the balcony
>monk finally shuts off machine, hulk turns to normal and falls to death
>druid turns into bird, has to choose between saving warlock or fighter from falling to death

I think i saved the warlock and crossed my fingers fighter would survive fall damage, and he did, just barely

Suggestion: Don't make it video games.

Train Boss - The enemy boss is approaching from the south and is far too strong for you to reasonably defeat, or even stand up against without getting torn to bloody shreds. To the north is an obstacle course full of enemies trying to slow you down. Can you get to the [plot area] before the bad guy catches you?

Twin/Triplet Boss - Keep their HP balanced, or the two with higher HP become stronger and stronger.

Danmaku Boss - The bad guy won't stop hurling slow moving projectiles in massive spiral patterns, holy shit how can you possibly keep track of how all these damn fireballs are moving?

Tower Defense Boss - The bad guy is trying to drain power from his willing minions, stop them from reaching him even as he is fighting you.

Defile Boss - Why is your friend glowing? Oh shit everything near him is dying! Now the ground he was standing on is blighted and you're the one glowing! Fuck!

>Danmaku Boss - The bad guy won't stop hurling slow moving projectiles in massive spiral patterns, holy shit how can you possibly keep track of how all these damn fireballs are moving?
How the fuck would you actually do this in a TRPG though?

The projectiles chase at a rate of 10/15 feet per round or some shit.

A bullet hell type series of spiraling fire attacks might be cool. even just jets fo fire walling off different characters

Quick time events, if they havent made their action rolled for it and got an outcome in 5 seconds they die
>this kills the mage

So does that mean that if the enemy doesn't roll his defense in 5 seconds, the mage's spell just automatically succeeds?

playing D&D with a grid, my DM is fond of bosses whose attacks leave hazards that can't be moved through without taking damage. Usually a big line of fire

You could be unoriginal and make the players fight themselves as manifestations of pride.

Another idea. is some kind of sumo wrestling boss, where in you fight him on a bridge or an edge and he tries to push people off using wind magic of sorts.

Another mechanic is the boss encases a player with something around the character and have to damage whatever is blocking their movement. usually followed up with a big attack that makes the player want to escape and not take a huge chunk of damage.

Seconding this wat

>basic D20(I think it's called GURPS)
>I am fairly new to GMing
Yeah, we can tell.

Did this to my players the last evening, kinda inspired by some bestiary I read a few months ago.

Boss is a freshly hatched Basilisk that lives in the canalisation under a big city. People suddenly start to get ill, the water is toxic and small animals die in its vile aura. The party is called to investigate the strange events. For every day that passes without them finding out the reason the basilisk grows and gets stronger.

The closer they get to the basilisk the more damage they will take per hour just from it's presence (Start with 1w6 and increase if necessary. When in combat with the basilisk start with 1w2 per combat round). Make some encounters in the sewers to strip them off their ressources.

The basilisk will petrify everything he looks at, a saveroll can be done depending on how close the player is and how much of his body was exposed. A fail will ultimately instantly kill a character. If a player touches the basilisk or his blood he will take 1W6 damage per combat round until he's dead or healed by magic.

Plan a map with severel different Pipes and corridors and stuff. Your players can escape and kite the basilisk through it but depending on how long the beast is, it can block a set amount of pasageways with his body. The group has to be carful not to get stuck or circled.

A basilisk is immune to poison and can swim but not climb. It can't hide or ambush and can't be disabled. It will always try to touch the players or petrify them.

To kill him with a mirror it's necessary to go into Melee range and make a roll handicapped by the size of the mirror. Going near the Basilisk also takes a will check. Blinding a basilisk is possible but sends him into a rage fastening it's movement on the map.