Welcome to . . . // Jurassic Park — ruling 1

If Welcome to… leaves the battlefield before its first chapter ability resolves, that ability will have no effect. The target noncreature artifacts won't become Walls at all.

Welcome to . . . // Jurassic Park — ruling 2

A noncreature permanent that turns into a creature can attack, and its {T} abilities can be activated, only if its controller has continuously controlled that permanent since the beginning of their most recent turn. It doesn't matter how long the permanent has been a creature.

Welcome to . . . // Jurassic Park — ruling 3

If you're casting an adventurer card or split card with escape, you choose how you wish to cast it, then pay the appropriate cost (for the Adventure, the creature, or the half of the split card you chose) plus exiling three cards.

Welcome to . . . // Jurassic Park — ruling 4

If a spell you're casting with escape has an additional cost of discarding cards or sacrificing permanents, you may exile cards discarded or sacrificed this way to pay that part of its escape cost.

Welcome to . . . // Jurassic Park — ruling 5

Escape's permission doesn't change when you may cast the spell from your graveyard.

Welcome to . . . // Jurassic Park — ruling 6

To determine the total cost of a spell, start with the mana cost or alternative cost you're paying (such as an escape cost), add any cost increases, then apply any cost reductions. The mana value of the spell remains unchanged, no matter what the total cost to cast it was and no matter whether an alternative cost was paid.

Welcome to . . . // Jurassic Park — ruling 7

After an escaped spell resolves, it returns to its owner's graveyard if it's not a permanent spell. If it is a permanent spell, it enters the battlefield and will return to its owner's graveyard if it dies later. Perhaps it will escape again—good underworld security is so hard to come by these days.

Welcome to . . . // Jurassic Park — ruling 8

If a card has multiple abilities giving you permission to cast it, such as two escape abilities or an escape ability and a flashback ability, you choose which one to apply. The others have no effect.

Welcome to . . . // Jurassic Park : règles, fonctionnement et interactions (MTG)

Welcome to . . . // Jurassic Park 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

(As this Saga enters and after your draw step, add a lore counter.) I — For each opponent, up to one target noncreature artifact they control becomes a 0/4 Wall artifact creature with defender for as long as you control this Saga. II — Create a 3/3 green Dinosaur creature token with trample. It gains haste until end of turn. III — Destroy all Walls. Exile this Saga, then return it to the battlefield transformed under your control. (Transforms from Welcome to ....) Each Dinosaur card in your graveyard has escape. The escape cost is equal to the card's mana cost plus exile three other cards from your graveyard. (You may cast cards from your graveyard for their escape cost.) : Add for each Dinosaur you control.

How it works : Welcome to . . . // Jurassic Park

Original English text — Wizards of the Coast / Scryfall

#1November 10, 2023· Wizards of the Coast
If Welcome to… leaves the battlefield before its first chapter ability resolves, that ability will have no effect. The target noncreature artifacts won't become Walls at all.
No other card is named in this ruling.
#2November 10, 2023· Wizards of the Coast
A noncreature permanent that turns into a creature can attack, and its abilities can be activated, only if its controller has continuously controlled that permanent since the beginning of their most recent turn. It doesn't matter how long the permanent has been a creature.
No other card is named in this ruling.
#3November 10, 2023· Wizards of the Coast
If you're casting an adventurer card or split card with escape, you choose how you wish to cast it, then pay the appropriate cost (for the Adventure, the creature, or the half of the split card you chose) plus exiling three cards.
No other card is named in this ruling.
#4November 10, 2023· Wizards of the Coast
If a spell you're casting with escape has an additional cost of discarding cards or sacrificing permanents, you may exile cards discarded or sacrificed this way to pay that part of its escape cost.
No other card is named in this ruling.
#5November 10, 2023· Wizards of the Coast
Escape's permission doesn't change when you may cast the spell from your graveyard.
No other card is named in this ruling.
#6November 10, 2023· Wizards of the Coast
To determine the total cost of a spell, start with the mana cost or alternative cost you're paying (such as an escape cost), add any cost increases, then apply any cost reductions. The mana value of the spell remains unchanged, no matter what the total cost to cast it was and no matter whether an alternative cost was paid.
No other card is named in this ruling.
#7November 10, 2023· Wizards of the Coast
After an escaped spell resolves, it returns to its owner's graveyard if it's not a permanent spell. If it is a permanent spell, it enters the battlefield and will return to its owner's graveyard if it dies later. Perhaps it will escape again—good underworld security is so hard to come by these days.
No other card is named in this ruling.
#8November 10, 2023· Wizards of the Coast
If a card has multiple abilities giving you permission to cast it, such as two escape abilities or an escape ability and a flashback ability, you choose which one to apply. The others have no effect.
No other card is named in this ruling.
#9November 10, 2023· Wizards of the Coast
If you cast a spell with its escape permission, you can't choose to apply any other alternative costs or to cast it without paying its mana cost. If it has any additional costs, you must pay those.
No other card is named in this ruling.
#10November 10, 2023· Wizards of the Coast
If a card with escape is put into your graveyard during your turn, you'll be able to cast it right away if it's legal to do so, before an opponent can take any actions.
No other card is named in this ruling.
#11November 10, 2023· Wizards of the Coast
Once you begin casting a spell with escape, it immediately moves to the stack. Players can't take any other actions until you're done casting the spell.
No other card is named in this ruling.