Splicer's Skill — ruling 1

The abilities spliced onto the spell happen last, after all of that spell’s other effects. Notably, the Golem won’t be on the battlefield yet if the spell has an effect that affects all creatures, all creatures you control, or similar.

Splicer's Skill — ruling 2

You reveal all cards you intend to splice at the same time. Each individual card can be spliced only once onto any one spell, although multiple cards with the same name may be spliced onto one spell.

Splicer's Skill — ruling 3

If a spell is copied, choices made while casting it are copied, so the copy will have the same abilities spliced onto it as the original.

Splicer's Skill — ruling 4

If the spell is countered, any cards you spliced onto it remain in your hand.

Splicer's Skill — ruling 5

If all of the spell’s targets are illegal when the spell tries to resolve, it won’t resolve and none of its effects will happen, including those from cards spliced onto it.

Splicer's Skill — ruling 6

The legality of a spell’s targets is checked only as that spell begins to resolve. If the spell this card is spliced onto causes its targets to become illegal while it’s resolving (for example, by removing them from the battlefield) you’ll still create a Golem.

Splicer's Skill : règles, fonctionnement et interactions (MTG)

Splicer's Skill 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

Create a 3/3 colorless Phyrexian Golem artifact creature token. Splice onto instant or sorcery (As you cast an instant or sorcery spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

How it works : Splicer's Skill

Original English text — Wizards of the Coast / Scryfall

#1June 14, 2019· Wizards of the Coast
The abilities spliced onto the spell happen last, after all of that spell’s other effects. Notably, the Golem won’t be on the battlefield yet if the spell has an effect that affects all creatures, all creatures you control, or similar.
No other card is named in this ruling.
#2June 14, 2019· Wizards of the Coast
You reveal all cards you intend to splice at the same time. Each individual card can be spliced only once onto any one spell, although multiple cards with the same name may be spliced onto one spell.
No other card is named in this ruling.
#3June 14, 2019· Wizards of the Coast
If a spell is copied, choices made while casting it are copied, so the copy will have the same abilities spliced onto it as the original.
No other card is named in this ruling.
#4June 14, 2019· Wizards of the Coast
If the spell is countered, any cards you spliced onto it remain in your hand.
No other card is named in this ruling.
#5June 14, 2019· Wizards of the Coast
If all of the spell’s targets are illegal when the spell tries to resolve, it won’t resolve and none of its effects will happen, including those from cards spliced onto it.
No other card is named in this ruling.
#6June 14, 2019· Wizards of the Coast
The legality of a spell’s targets is checked only as that spell begins to resolve. If the spell this card is spliced onto causes its targets to become illegal while it’s resolving (for example, by removing them from the battlefield) you’ll still create a Golem.
No other card is named in this ruling.