They’re the best boys and goodest girls and impossible to keep track of. They’re the Blink Dogs!

Of all the creatures that your party might try to adopt out of their sheer cuteness, the Blink Dog is likely to be very high on the list. They’re dogs! For a DM, they can look like whatever kind of dog you want. In fact I think that is something you should exploit when the circumstances arise, and it might give you some variety and amusement. After all, a Blink Pug is going to be very different from, say, a Blink Doberman.

However you flavor your Blink Dog, they seem to have in-game qualities that make them comparable to dogs in general. Statwise, they are somewhat comparable to a Wolf or a Mastiff, with a few important distinctions.

With a 10 in Intelligence, a 13 in Wisdom, and an 11 in Charisma, they match or surpass many of your average humanoids, making them not only clever but capable of strategy and communication.

This tells you something important: Blink Dogs are intelligent, thinking creatures, and you really should run them as such. That might throw your players for a loop if the Blink Dog is an enemy: the Players will expect doglike behavior and instead get some more considered strategy. And if they try to keep one as a pet, you would be well within your rights to have the Blink Dog refuse to be kept. It is a Fey, after all, and the Fey do not like being bound.

The most important feature of the Blink Dog, of course, is the Blinking: every six seconds they have a 50% chance to be able to teleport up to 40 feet away as a Bonus Action. In combat, of course, this can be a source of great obnoxiousness: Run up to the barbarian, gnaw on her leg, and then Blink out before she has a turn to do anything. You could even have them Blink in next to a Ranged Player, who will then have disadvantage on attacking the doggo on their turn.

It’s like fun, fey whack-a-mole! With teeth!

In a way, the Blink Dog is an eternal hyperactive puppy: everywhere you don’t want it to be, and almost impossible to pin down. Good thing they’re Lawful Good… which is weird for a Fey, if you ask me, but I suppose even the Fey need hall monitors.

If you want to beef up your Blink Dog, you can make a few tweaks that will throw off players who think they know what they’re in for. One thing I would do is tinker with its teleportation ability. For example, give them Thunder Step, a 3rd-level spell that makes a thunderous boom in the place you vanish from, potentially damaging nearby enemies.

And if that’s not fun enough, there’s no reason you can’t use another type of damage – lightning, cold, fire, acid, etc. – which implies a variety of Blink Dog species. Imagine how annoyed your players could be! An Emberblink from a rift near the elemental plane of Fire! A Frostblink from the far reaches of Everwinter! A Necroblink dog from the border of the Shadowfell. The possibilities are endless, and should give even seasoned players a pause.

You might also give it some other spellcasting, since it has solid stats in the spellcasting department. Detect Thoughts might be interesting in a roleplaying sense, or Faerie Fire for combat.

The best spell to give it, though? Friends. Because it’s a good dog, and who wouldn’t want to be friends with it?

Here’s a few encounter seeds for you:

• A Fey Lord has possession of a valuable gem that you need for your mission. That valuable gem is currently attached to the collar of one of his many pet Blink Dogs. Good luck.
• A village has been losing chickens to what the locals swear is a Ghost Hound. It’s a Blink Dog trying to find a way back to the Feywild, and it has a very loose understanding of “property.”
• Deep in the Feywild, a small child has found their way from their world. Lost and alone, the child befriends a Blink Dog, who has chosen to protect and guide them until they can get home.
• An unscrupulous wizard has found a way to limit the Blink Dog’s abilities and is training them as fighting dogs for his own evil endeavors.
• A Blink Dog decides that one of your players is their Special Person, whether your player wants it or not. Bonus points if that character is the gruffest, grumpiest one in the Party.
• Your players wander into the middle of a brawl between a pack of Blink Dogs and their eternal enemies: The Displacer Beasts!

So there you go! Go put a Blink Dog in front of your party and see what happens.