Sudden Shock — ruling 1

Players still get priority while a card with split second is on the stack; their options are just limited to mana abilities and certain special actions.

Sudden Shock — ruling 2

Players may turn face-down creatures face up while a spell with split second is on the stack.

Sudden Shock — ruling 3

Split second doesn't stop triggered abilities from triggering, such as that of Chalice of the Void. If one does, its controller puts it on the stack and chooses targets for it, if any. Those abilities will resolve as normal.

Sudden Shock — ruling 4

Casting a spell with split second won't affect spells and abilities that are already on the stack.

Sudden Shock — ruling 5

If the resolution of a triggered ability involves casting a spell, that spell can't be cast if a spell with split second is on the stack.

Sudden Shock — ruling 6

After a spell with split second resolves (or otherwise leaves the stack), players may again cast spells and activate abilities before the next object on the stack resolves.

Sudden Shock : règles, fonctionnement et interactions (MTG)

Sudden Shock is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.) Sudden Shock deals 2 damage to any target.

How it works : Sudden Shock

Original English text — Wizards of the Coast / Scryfall

#1March 19, 2021· Wizards of the Coast
Players still get priority while a card with split second is on the stack; their options are just limited to mana abilities and certain special actions.
No other card is named in this ruling.
#2March 19, 2021· Wizards of the Coast
Players may turn face-down creatures face up while a spell with split second is on the stack.
No other card is named in this ruling.
#3March 19, 2021· Wizards of the Coast
Split second doesn't stop triggered abilities from triggering, such as that of Chalice of the Void. If one does, its controller puts it on the stack and chooses targets for it, if any. Those abilities will resolve as normal.
No other card is named in this ruling.
#4March 19, 2021· Wizards of the Coast
Casting a spell with split second won't affect spells and abilities that are already on the stack.
No other card is named in this ruling.
#5March 19, 2021· Wizards of the Coast
If the resolution of a triggered ability involves casting a spell, that spell can't be cast if a spell with split second is on the stack.
No other card is named in this ruling.
#6March 19, 2021· Wizards of the Coast
After a spell with split second resolves (or otherwise leaves the stack), players may again cast spells and activate abilities before the next object on the stack resolves.
No other card is named in this ruling.