Lesser Dog's fur is a light cream color, and its red tongue appears to be perpetually lolling out of its mouth. It wears gray, presumably metal armor with a darker gray band around the waist area. It holds a sword and a shield with the Delta Rune.
Like several other dog characters, Lesser Dog becomes overexcited from physical attention. It is capable of extending its neck at a seemingly limitless rate when stimulated by being pet.
Lesser Dog appears to enjoy spending its time off sentry duty by playing card games (namely, poker and go fish) against itself at Grillby's. When interacting with it at this time, the text mentions how it appears to be losing.
While waiting around its sentry post in Snowdin Forest, Lesser Dog spends a lot of its time making snowdogs, mostly with necks in similar lengths to its own. A faun monster standing near the post notes that it seems to get overexcited in the construction of the figures and never finishes them. It may be that Lesser Dog is able to achieve focus by being pet, as after being pet by the protagonist its statues will become more complete, and the more pets it receives the more statues Lesser Dog creates around its sentry post, until they all become broken statues of its very long neck when it is pet enough times or has the Stick thrown at it. In this case, the faun states that a dog came by full of excitement and started building sculptures, but its neck kept growing and it kept adding snow to the sculptures until they broke. On the flip side, if Lesser Dog is killed, its sentry post will be accompanied only by a pile of formless mushy snow.
In the playable epilogue for the True Pacifist Route, Lesser Dog has, apparently, finally won a game of poker against itself, sitting in Grillby's bar - the only dog character not to be outside the Snowdin Library playing with its family member(s) Endogeny. In the True Pacifist Ending Credits, it can be seen building sand dogs on the beach.
- A dog resembling the Annoying Dog appears to the right of the screen and runs on the spot for a moment before leaping to where the protagonist's SOUL is. If the dog did not jump far, it is possible for the dog to start to jump as the attack ends.
- A blue spear comes in from the right of the screen and moves all the way to the left, followed by a white spear coming in from the left, stopping in the middle and moving back leftwards for a moment before the attack ends.
- Lesser Dog will cease attacking once pet six times ("Critical pet!").
It is very easy to spare Lesser Dog.
- If you pet Lesser Dog once, you can spare it. If you keep petting it, its head will keep rising, eventually ceasing its attacks, surpass the dialogue box, and even the menu. Lesser Dog can be pet 54 times before petting it will not trigger new messages.
- Like other dog enemies, the Stick can be used to end the Lesser Dog battle instantly.
- (Pant pant) [Encounter]
- (Tiny bark) [Neutral]
- (Wag wag) [Neutral]
- (Thinks of food) [Neutral]
- (Pant! Pant!) [Pet #1-3]
- (Excited noises) [Pet #4-6]
- (Motor revving) [Pet #7]
- (Plane takeoff) [Pet #8]
- (Kettle whistle) [Pet #9]
- (...) [Pet #10]
- (Faraway bark) [Pet #11]
- (...) [Pet #12]
- (Bark) [Pet #13]
- (Pant pant) [Pet #14+]
- Wields a stone dogger made of pomer-granite. [Check]
- Lesser Dog appears. [Encounter]
- Lesser Dog cocks its head to one side. [Neutral]
- Smells like dog chow. [Neutral]
- Lesser Dog thinks your weapon is a dog treat. [Neutral]
- Lesser Dog is really not paying attention. [Neutral]
- You barely lifted your hand and Lesser Dog got excited. [Pet #1]
- Lesser Dog is barking excitedly. [After Pets #1-3]
- You lightly touched the Dog. It's already overexcited... [Pet #2]
- You pet the Dog. It raises its head up to meet your hand. [Pet #3]
- You pet the Dog. It was a good Dog. [Pet #4]
- Lesser Dog is overstimulated. [After Pets #4-7]
- You pet the Dog. Its excitement knows no bounds. [Pet #5]
- Critical pet! Dog excitement increased. [Pet #6]
- You have to jump up to pet the Dog. [Pet #7]
- You don't even pet it. It gets more excited. [Pet #8]
- Lesser Dog shows no signs of stopping. [After Pets #8-13]
- There is no way to stop this madness. [Pet #9]
- Lesser Dog enters the realm of the clouds. [Pet #10]
- You call the Dog but it is too late. It cannot hear you. [Pet #11]
- ... [Pet #12]
- You can reach Lesser Dog again. [Pet #13]
- You pet Lesser Dog. [Pet #14-19]
- Lesser Dog is lowering. [After Pets #14-19, 27-31]
- It's possible that you may have a problem. [Pet #20-32]
- Lesser Dog is learning to read. [After Pets #32-33]
- Lesser Dog is unpettable but appreciates the attempt. [Pet #33-34]
- Lesser Dog is whining because it can't see you. [After Pets #34-42]
- Hello there. [After Pets #43-45]
- Perhaps mankind was not meant to pet this much. [Pet #44]
- It continues. [Pet #45-51]
- Lesser Dog is questioning your choices. [After Pets #46-52]
- Lesser Dog is beyond your reach. [Pet #52-53]
- Lesser Dog has gone where no Dog has gone before. [After Pets #53-54]
- Really... [Pet #54+]
- You threw the stick and the dog ran to get it. You played fetch for a while. [Use Stick]
- Lesser Dog tucks its tail between its legs. [Low HP]
- Lesser Dog's name derives from the constellation Canis Minor, which is Latin for "lesser dog."
- Lesser Dog has a weapon called a dogger, as mentioned in the CHECK text, which is a pun on the word "dagger."
- The Red Bird NPC in Grillby's will comment on the disappearance of the Dogs, even if Lesser Dog is still alive.
- Interestingly, Lesser Dog is never mentioned by the other guard dogs. Killing it provokes no reaction from the other dogs at Grillby's. In turn, if Lesser Dog is the only guard dog left, how it acts at Grillby's does not change.
- If Lesser Dog is the only enemy that you have killed, Undyne will comment on it, claiming that it was only seeking affection.
- The encounter of Lesser Dog is completely random, like normal enemy encounters. It is always killed on a Genocide Route, though it is possible to move through Snowdin on a Neutral or True Pacifist Route without encountering it.
- Lesser Dog's guard post contains a box of pomeraisins, and its weapon is made of pomer-granite. The joke here is a reference to the breed of dogs known as Pomeranian.
- Lesser Dog is mentioned by the River Person as they say: "Pet pet pet... The neck stretches infinitely into the cosmos. ...Don't worry about it." This is also a reference to the easter egg that can be achieved by petting it at least 54 times.
- Lesser Dog is the only Royal Guard member that is not a boss or miniboss.