If the adversary holding Mr. Nibbles' leash is within Very Close range, increase their Difficulty by 2 as Mr. Nibbles actively parries attacks targeting them.

Mr. Nibbles' collar and leash contain a powerful enchantment that reduces his size, strength, and power and locks him into servitude of whoever put the leash on him, or their designate. The collar can be targeted during a fight, in which case it has a Difficulty of 20 and is destroyed after 3 successful attacks or can be removed with a Finesse roll with disadvantage. If the collar is destroyed or removed, Mr. Nibbles grows to his original prodigious size, breaking any building or other constraint as he grows. Replace this adversary with Nargalothus, The Flame of 1000 Sorrows.

When a PC within Far range makes a successful attack roll against the adversary holding Mr. Nibbles' leash, mark a Stress to have Mr. Nibbles breathe fire on them. They must make an Agility reaction roll. On a failure, they take 3d20 magic damage. On a success, they take half damage.

If the adversary holding Mr. Nibbles' leash is defeated, he will plead with the PCs to break his collar and free him. If this happens, the collar can be broken with 3 attacks, which succeed automatically, or removed with a Finesse roll. The PCs can choose to make an Instinct reaction roll to sus out Mr. Nibbles' motives. Mark a Stress to add his Deceptive Experience to the Difficulty of this roll. On a success, they get a sinking feeling that releasing him would be a very bad idea.