Sulfur Elemental

Because damage remains marked on a creature until the damage is removed as the turn ends, nonlethal damage dealt to white creatures may become lethal if Sulfur Elemental enters the battlefield during that turn.

Wotc — March 19, 2021

Players can't take actions between the time that Sulfur Elemental enters the battlefield and the time state-based actions are performed.

Wotc — March 19, 2021

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.

Wotc — March 19, 2021

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

Wotc — March 19, 2021

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.

Wotc — March 19, 2021

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

Wotc — March 19, 2021

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.

Wotc — March 19, 2021

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.

Wotc — March 19, 2021