Weaker Smaller Creatures (5e Variant Rule)
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Weaker Smaller Creatures
D&D 5e has a slight oddity when dealing with Small and Tiny creatures: their weight limits. For example, a gnome can carry just as much weight as a human, provided they have the same Strength score. And my cat can carry another cat on its back without even breaking a sweat. While funny to imagine, I do not believe that a halfling should be able to carry 5 other halflings at once without the help of bionic implants or spells or something.
This variant rule seeks to fix this slight break in immersion with one simple change: Similarly to how each of your weight limits (i.e. carry capacity, max lift/drag/push, etc.) are doubled for each size you are above Medium, each of your weight limits are halved for each size you are below Medium. This means a Small creature with a Strength score of 10 can carry only 75 lbs instead of 150, and a Tiny creature with a Strength score of 4 can carry a mere 5 lbs instead of 10.
When combined with the Variant: Encumbrance rule on page 176 of the PHB, Small creatures are encumbered when carrying weight in excess of 2.5 times their Strength score, and are heavily encumbered when carrying weight in excess of 5 times their Strength score. Tiny creatures are encumbered when carrying weight in excess of a mere 1.25 times their Strength score, or are heavily encumbered when the weight exceeds 2.5 times their Strength score.
Because of the difference in weight limits granted by this rule, armor and clothes worn by Small and Tiny creatures have their weight reduced in the same way. You could also rule that the cost of such gear is also reduced by some amount, as it takes less materials to make. Weapons and other adventuring gear does not have its weight reduced, as their effectiveness is often based on their size and weight. The things that make a longsword a longsword no longer apply if the sword is made smaller. However, plate armor is still plate armor regardless of its size, and clothing is clothing. This addition to the variant rule is to help balance the problem of too many heavy things.
Another balancing factor is the quantity of food and water required by Small and Tiny creatures to survive. For each size you are below Medium, halve the amount of food and water you need each day to survive. The main purpose of this addition is to (again) reduce the required weight for the average adventuring Small character. With this, a halfling needs only 5 days worth of rations to eat for 10 days, halving the weight of the food they'll need to carry for the journey. Likewise, it makes very little sense for a pixie to eat a minimum of an entire hamburger (with toppings) just to survive, since a day's worth of rations is the minimum amount of food a Medium creature needs to continue to survive, not live comfortably. Imagine eating half your body weight every day just so you don't starve, or drinking an entire bathtub of water every day just so you don't experience death by dehydration: yes, I know lions do that, but we aren't lions, and neither are gnomes, halflings, or pixies and sprites. With this addition, the entire hamburger is a meal of luxury for the pixie, while just the patty is what they need to merely persist from day-to-day. Side note: if you're a fan of the Lord of the Rings series and like having your halflings resemble the gluttonous hobbits from the franchise, just ignore this for them. Go ahead and let your halflings be the tiny vacuum cleaners of the realm! And the part about the water helps prevent pixies from downing your entire waterskin in just one day, which holds enough water for them to take a bath in. (Waterskins in 5e are massive: half a gallon of water takes up more space than most of us realize.)
Even though we all laugh at and love the idea of a 20-Strength gnome who is a Totem Warrior (Bear) Barbarian carrying a whopping 600 lbs in their backpacks (or dragging a full 1,200 lbs across the ground), it's not very realistic. Gnomes only weigh about 40 lbs. For comparison, the average untrained human in the real world can only carry between 50-100% of their own body weight, and even then only for short distances. This means that in the D&D world, where everyone is at least somewhat physically fit, your NPC human commoner is capable of carrying their full body weight. With this information, it seemed weird that the average gnome can carry 300% of their body weight with ease. It's even weirder to think of a house cat dragging three other cats at once with only some effort. I mean, yeah, the cats I live with are strong, but the cats in my house are literally 50% bigger than the average cat, which is what D&D 5e uses.
This rule can drastically nerf the abilities of your players who like playing Small races or even the homebrew Tiny races, especially if you use the Encumbrance rule, since a gnome with a Strength of 14 under both rules will have their speed reduced by 10 feet while carrying a mere 35 lbs. For reference, most packs in the game (such as the Dungeoneer's pack) weigh more than this, and the character doesn't have weapons, armor, or even clothes yet!
If you have other crazy examples of strange weight limits or portion sizes for certain creatures, the discussion page is always open, and it would probably be fun to laugh and joke at just how much (or, in certain cases, how little) food some of the base creatures eat.