Line of sight is not important, a clear path to target is. Read up on the difference between concealment and cover. Fog doesn't stop spells but a wall does.

My Dm allowed me to use this on a tree in the road... i rolled a nat 20 and the tree instantly decayed... wtf

"... and it can't regain hit points until the start of your next turn."

That is way to ominous to describe how the hit points are gained:
- gain HP via the creatures regeneration ability
- gain temporary HP via a spell, area effect etc.
- gain HP via drinking a potion
- gain HP via a magic item (e.g. hit a creature, gain 1/2 the HP of damage dealt)
- gain HP via a dedicated healing spell

This is the only necrotic cantrip I can find so stop hating haters 

No 

just

no

It hangs on for multiple rounds, until your next turn. As it says in the description. So if you're working a 3 man party, that doesn't come about until after, person 2, bad guy, and person 3 go.

So at level one that's four/three d8s of necrotic, no health regen, on top of the damage your buddies are doing.

Not allowing a creature to regain hit points, like a boss, without even it making a saving throw can be really helpful for the rest of the party

Mmm... think I'm homebrewing this to "Graves Reach" so it does counter undead fortitude feel it's kind of intended to

yis

Yes it does at least from my experience.

Quote from Ziato_the_Forgotten >>

It hangs on for multiple rounds, until your next turn. As it says in the description. So if you're working a 3 man party, that doesn't come about until after, person 2, bad guy, and person 3 go.

So at level one that's four/three d8s of necrotic, no health regen, on top of the damage your buddies are doing.

 The effect lasts for the healing debuff, not damage re-occurrence.  There is only a single damage die result, but the target can't regain HP until it's the caster's turn again. 

Spell Casting Word is:

Britalus Grasipicus

does chill touch always hit?

Quote from Yakobine >>

does chill touch always hit?

No. The spell description says "make a ranged spell attack", so you make an attack roll to see if it hits.

i popped a head o with this spell 

Would the spell's debuffs work on an enemy that is immune to necrotic damage?

Quote from GriffarkLongtail >>

Would the spell's debuffs work on an enemy that is immune to necrotic damage?

Yes. Being immune to a particular type of damage doesn't have any impact on other effects caused by a source of that damage type. A creature that is immune to necrotic damage would still be unable to heal if hit by this spell, as well as still having disadvantage on attacks against you if it's undead.

My favorite part of this spell is that it chills when you touch.

Does Immunity to Necrotic damage make you immune to the secondary effects of this spell

I would rule that it does not make you immune to the secondary effects because the "ghostly, skeletal hand" is still grabbing the target, it just didn't do any damage. Also, it says, "On a hit, ... the hand clings to the target." And the effect on Undead also says, "If you hit..." Not if you do damage. So I would rule that it does still have the secondary effects. 

Edit: Not sure if there has been any thing said officially about it, but this is how I would run the spell at my table if it came up.