I have plans for a Paladin to encounter an "undead treant" whose CR is far above her level. I am taking much of my inspiration from this creature as seen here, and one ability in particular has me curious.
Given that 'diseases' in 5e generally have a mid- to long-term incubation period and require saves, and this infestation's incubation is immediate with no saving throw, would you rule that Fungus counts or does not count as a 'disease' for purposes of Paladin immunity?Fungus (Ex)
The [undead treant]’s branches are encrusted with a virulent fungus that grows rapidly when in contact with blood, sending filaments ripping through the bodies of any living creatures damaged by its slams and dealing 1d6 points of Dexterity damage in the process. A creature brought to 0 Dexterity by this effect is slain.