D&D: Guinea Pigs & Were-Guinea Pigs

My daughter Hannah goes to an agricultural high school in Trumbull, and what with COVID-19 having shut down the planet, we’re currently hosting her class’s guinea pigs.  It turns out that they make good pets.  They’ve become family favorites, which means that it’s now time to figure out how to work them into our home Dungeons & Dragons campaign.

Yours truly with Giblet, the Lord of Guinea Pigs.

If you've never been around guinea pigs, then you might not realize how loud and distracting they can be.  My base theory is that they're mostly useless in combat save for this ability to serve as a distraction.  However, there are any number of ways that they might work in-game beyond simple combat.  Thinking through some of that has been an interesting exercise.

Some few adventurers train guinea pigs for work in the field.  Guinea pig animal companions most often work as scouts or perhaps may simply serve as friendly company in dire situation, but a rare few learn to pick locks and perform similar “thievery” services.  In such cases, the guinea pigs’ claws act as thieves tools, with which the animals -- and their masters -- are proficient. 

Were-Guinea Pigs

Thankfully, the strain of lycanthropy that causes the change to guinea pig is vanishingly rare.  This is mostly because it affects a relatively minor portion of the sentient population, small-sized mammalian humanoids.  Thus, halflings, gnomes, and even goblins can become were-guinea pigs, but humans, elves, dwarves, and even kobolds are immune to this little-known disease.

Were-guinea pigs share most physical and social traits with members of their origin race, though like all lycanthropes they remain firmly tied to their transformations and to the phases of the moon.

Were-Guinea Pig Features

Ability Score Increase. Were-guinea pigs are generally cute and harmless-looking, even when in the form of their origin race.  For this reason, a were-guinea pig’s Charisma score increases by 2.

Age. Were-guinea pigs mature as members of their origin race.

Alignment. Any chaotic.  Halfling and gnomish were-guinea pigs lean towards chaotic good while goblin were-guinea pigs lean towards chaotic evil.

Size. Were-guinea pigs average about 3 feet tall and typically weigh just under 40 pounds. They are size small.

Speed. 30 feet.

Cute. You gain advantage on Charisma-based skills checks made to appear harmless or non-threatening.

Guinea Pig Senses. Were-guinea pigs cannot see with their eyes quite as effectively as is typical for their origin race, but their enhanced hearing, whiskers, and sense of smell easily make up the difference.  Though were-guinea pigs are universally color-blind, they can use their senses in combination to perceive in dim light as if it were bright out to a range of 60 feet.  In darkness, they perceive as if in dim light.  This effect is mechanically identical to darkvision. 

Lycanthropic Transformation.  As an action, were-guinea pigs can transform, changing freely between any of their three shapes: humanoid, half-guinea pig, and full guinea pig.  However, when the moon is full and clearly visible in the night sky, were-guinea pigs transform involuntarily into their full guinea pig form and must remain in that form until the next dawn.

• Humanoid.  This is the creature’s base form, with its normal humanoid attributes.
• Half-Guinea Pig.  This is the creature’s were-form.  It retains the size and speech abilities of its origin race, but it gains the fur, claws, and snout of a guinea pig.  In this form, the were-guinea pig can use the power Week Week Week as a bonus action once every long or short rest.  It also makes Stealth checks with advantage when in close or confined spaces.  Despite having claws, half-guinea pigs can hold and use weapons and other adventuring equipment as normal.
• Guinea Pig.  The were-guinea pig transforms into its full animal form, gaining all the powers, abilities, and restrictions of a typical guinea pig.  Creatures in this form are size tiny.  If the were-guinea pig is proficient with thieves tools, it can use its claws as thieves tools and add its proficiency bonus.  A were-guinea pig cannot speak or cast spells in this form, but it can still think and understand language as normal.

Languages. Were-guinea pigs can speak, read, and write Common and the language of their origin race, be it Halfling, Gnomish, or Goblin.

Halfling Were-Guinea Pig

• Ability Score Increase. Dexterity score increases by 1.

• Brave. Halfling were-guinea pigs have advantage on saving throws against being frightened.

Gnome Were-Guinea Pig

• Ability Score Increase. Intelligence score increases by 1.

• Fey Cunning. Gnome were-guinea pigs have advantage on all Intelligence, Wisdom, and Charisma saving throws against magic.

Goblin Were-Guinea Pig

• Ability Score Increase. Constitution score increases by 1.

• Nimble Escape. A goblin were-guinea pigs can take the Disengage or Hide action as a bonus action on each of its turns.