Counterspell - 3rd level abjuration
Casting Time: 1 reaction, which you take when you see a creature within 60 feet of you casting a spell Range: 60 ft Components: S Duration: Instantaneous
You attempt to interrupt a creature in the process of casting a spell. If the creature is casting a spell of 3rd level or lower, its spell fails and has no effect. If it is casting a spell of 4th level or higher, make an ability check using your spellcasting ability. The DC equals 10 + the spell’s level. On a success, the creatures’ spell fails and has no effect. At higher levels. When you cast this spell using a spell slot of 4th level or higher, the interrupted spell has no effect if its level is less than or equal to the level of the spell slot you used. Classes: Sorcerer, Warlock, and Wizard
Can you counterspell a counterspell?
Yes. This can be chained, so long as the casters involved haven’t already used their reactions. You could potentially have a dozen spellcasters counterspelling each other in an epic battle to fight over an original spell being casted.
Can you counterspell magic items?
If the item specifies a spell being cast, then yes.
Can you counterspell yourself?
While the spell says that you are trying to interrupt casting, it’s debatable if you can really interrupt yourself. However, if you’re asking this, it’ll probably make for either a dramatic or funny moment, so probably yes.
Can you counterspell cantrips?
Yes. Cantrips are considered level 0, which is automatically counterspelled.
Can you counterspell abilities?
No. It counters spells, not abilities.
How to beat counterspell?
Remember these key factors:
It’s range is only 60ft
It requires a reaction, and you only get 1 per round
It requires an ability check above level 3
It can be counterspelled
What cannot be counterspelled?
Innate abilities that do not specify “casting” as part of their action cannot be counterspelled. That said, the DM is always there to rule for exceptions.
Can you counterspell a magical item, status, or object?
No, counterspell interrupts the process of casting a spell. Items, status, objects, or creatures already have the spell on them and would need dispel magic to be used to nullify their affects.
Can you counterspell innate spellcasting?
Yes. Although the spell is not using a spell slot as spellcasting does, it is still considered casting a spell.
Can you counterspell creatures with magic immunity?
As the spell targets a creature casting a spell, it’s immunity would affect that spell. Many point out the distinction of targeting the spell vs the caster, which is usually met with the point that the spell notes seeing a creature casting the spell.
Ultimately the DMs ruling, but Jeremy Crawford has supported this point too:
https://twitter.com/JeremyECrawford/status/792412232432758784
Mym's Well 