Gru's small sharp-toothed pet dog is named Kyle. He lives with Gru and the Minions in the first Despicable Me film and is recognizable for his prickly, aggressive appearance despite being a household pet.
Kyle fits the strange domestic world beneath Gru's suburban home. Gru presents himself as a supervillain, but his secret lair is also where he raises his adopted daughters, works with Dr. Nefario, and keeps his unusual dog. Kyle's sharp teeth and gruff behavior make him look threatening, yet he functions as part of the chaotic family surrounding Gru.
The name is easy to mix up with the many other short names in the franchise. Gru's daughters are Margo, Edith, and Agnes, while his Minions include Kevin, Stuart, Bob, Dave, and Otto. Kyle is not a Minion or a weapon; he is Gru's pet. Later films expand Gru's family and introduce other pets and creatures, but Kyle remains the canonical answer to this question about Gru's small dog.