#spidershark

Monsters should have a unique presence

When designing a new monster, think about its presence. How do the players see this monster? How do the characters see it? Does it loom over them? Does it hide in the darkness waiting to strike? A monster with presence has a distinctive visual feature, evocative attitude, focused mechanics, and a memorable experience in and out of character.

image credit: Ben Wootten

If similar to existing monster, make it distinct

The monster we made at the panel started out conceptually as a "land shark." There is a particularly famous creature already known as a land shark called the Bulette. So when designing our creature we had to keep in mind that this other creature already existed. We had to think up new ways for this new land shark to not be a mere copy of the Bulette. We made ours climb like a praying mantis rather than burrow like a sort of stout rhino. We also gave it unique webbing to distinguish it from the Bulette. It's CR is also quite higher (we went for about CR 9 while a Bulette is about CR 5). Combat with either a Bulette or our new land-shark would go entirely differently. Just as their looks separate them, so too do their mechanics.

Compare to Other Challenge Ratings

Our land-shark creature was about on-par with a Fire Giant, we decided, which is CR 9. So when designing the mechanics, we ensured that this thing would be just about as difficult to fight as such a creature. This is useful in pretty much all homebrewing. By comparing to an existing standard, you can get an idea of how powerful or balanced your creation is. For instance, while a fire giant has a ton of damage and a ranged rock throw attack, our land shark had barbed, explosive webbing and the ability to climb up walls. This makes our creature present a unique challenge through its utility and mobility. When compared to the Fire Giant, we should tone down our damage to let that webbing deal some damage of its own, and perhaps tone down our HP since our creature is a bit more stealthy and likely to ambush the players, frontloading them with its web burst in the surprise round and then a full-on attack in the first round. Without comparison, we can't balance anything.

image source: Yiazmat from Final Fantasy XII.

Easy for a DM to describe

As cool as having any Final Fantasy character boss monster in your campaign would be (ah yes, the ole metal xenomorph finned spearhead clawtail dragon with magic patterned circles for a head/tail/wings), if it takes longer to describe the monster to your players than it does for them to kill it, you're doing it wrong. Use familiar animals or common forms to describe monsters. This is likely why a lot of creatures are two monsters mashed together; it's easy to see in your mind's eye. "Your party encounters an Owlbear." More owl or more bear? "More bear. It has a beak, though." Got it. See how easy that was? If you use something the player is already familiar with they can easily grasp what you're saying. This is the benefit of writing descriptions for your homebrew monsters instead of completely relying on a picture. It sparks the imagination while aiding in immersion.

Monster-Campaign Interaction

Keep in mind how the monster interacts with your setting and world, as well as the players. Where does this creature live? Does it hunt for food or wait to trap creatures in its lair? Is it territorial? How does it interact with other species? Is it symbiotic with another creature or race? Could you ride it? Ask all of these questions and more too deepen the creature’s lore and its place in your world.

Using the Recharge mechanic

The recharge mechanic (used on one of our land-shark’s abilities) is used as a mechanical increase to anticipation. The creature can use their recharge ability potentially every turn (if the players are unlucky enough) but not necessarily. This unknown value between the players and the DM increases the tension. Will it use it again, or will it still be on cooldown? Who knows! Even veteran players that know a dragon’s breath has the recharge ability won’t be able to predict how often it’s used. Add the recharge mechanic to make monsters more intimidating and place it on powerful abilities (since technically, on average, it can only use it once every three turns if it’s recharge 5-6, or every other turn with 4-6).

image credit: Noblecrumpet (me)

The Shark that Walks (CR 9)

They gave the land-shark web sense like a spider, but I thought I would give it something more related to sharks so I let it smell bloodied creatures instead. Other than that, this is the monster the audience came up with to the best of my recollection. I also doodled my own version while we were brainstorming, but mine ended up being a bit more Aberration than Monstrosity 

Large Monstrosity

AC 16; HP: 143 (12d10+72); SPD: Move 30 ft., Climb 30 ft.

STR 22; DEX 17; CON 23; INT 3; WIS 10; CHA 4

Skills: Stealth +7, Perception +4

Spider Climb: The Shark that Walks can climb difficult surfaces, including upside-down on ceilings, without needing to make an ability check.

Blood Sense: The Shark that Walks knows the exact location of any other creature within 120 ft. at half of its maximum hit points.

Web Walker: The Shark that Walks ignores movement restrictions caused by webbing.

Actions

Multiattack: The Shark that Walks can make one claw and one bite attack when it takes the attack action.

Barbed Web: Ranged Weapon Attack: +7 to hit, range 30/60 ft., one creature. Hit: The target is restrained by webbing and takes 3d6 (11) piercing damage each round while restrained by the webs. As an action, the restrained target can make a DC 16 STR check, bursting the webbing on a success. The webbing can also be attacked and destroyed (AC 12; hp 12; vulnerability to fire damage; immunity to bludgeoning, poison, and psychic damage)

Bite: Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 2d10+6 (17) slashing damage. 

Claws: Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 4d8+6 (24) slashing damage.