This works great on doors.

Like, to break locks?

Like to destroy the door xD

xD

Last session, cast shatter on a really tough monster. Did little to no dmg to her, but destroyed a runed spike in its leg controlling it we didn't even know about. Great DMing!

Casting spellword is:

Explodicus Loudinium

Do constructs shrug off your vicious mockery? Try hurting them physically rather than emotionally with Shatter!

Now with disadvantage! Order now, I'll throw in thunder damage. Absolutely free!

How would you rule casting this on a skeleton? Would it have disadvantage on the save or not?

Bone is organic.  So no, skeletons would not.

Bone golems are immune to all spells, spell-like abilities, and supernatural effects, except as follows. Focusing a shatter spell strong enough for something of its weight on the golem will weaken it structurally. This will allow slashing and piercing weapons that are able to damage it to do full damage and bludgeoning weapons that are able to damage it to deal double damage. So it could affect a skeleton to.

Technically, Elementals are made of inorganic material. So if you use this spell on a fire elemental, would it impose disadvantage? The rules don’t say that the spell is limited to substances such as rock, it only uses them as examples. What do you guys think?

Well, i would rule that it would impose a disadvantage due to the loud sound disrupting the magic holding it together.

Is this worth keeping as a 10th level warlock or should I switch it out?

What about warforged,they are made of both inorganic and organic material,and what if ur PC has a prosthetic limb?

Yes, definitely. If you use higher level spell slots, the damage is increased by 1d8 for every slot above 2nd level:)

Fire isn't a material (organic or inorganic), but air, earth, & water qualify, sure.

Quote from Jaeken >>

Fire isn't a material (organic or inorganic), but air, earth, & water qualify, sure.

 Fire is really just hot air though. When something is burning, the air around it and the gasses produced by the proccess gets so hot it all starts to glow, and that glowing air is what we call "fire".

Cleric, Tempest Domain, 9th level slot, Shatter, channel your god and boom, 80 damage to anyone in the radius. Though I feel it should get a minor AOE bonus if you use higher level spell slots.

If I center this on myself (when surrounded by enemies) would I be immune to its effects?  RAW would seem to indicate NO ("Each creature in a 10-foot-radius sphere centered on that point" -- I am a creature, ergo...)

Delayed cast + blink perhaps?