Turtle Van

Crew is an activated ability of Vehicle cards. “Crew N” means “Tap any number of other untapped creatures you control with total power N or greater: This permanent becomes an artifact creature until end of turn.”

A creature “crews a Vehicle” when it’s tapped to pay the cost to activate a Vehicle’s crew ability.

If an effect states that a creature “can’t crew Vehicles,” that creature can’t be tapped to pay the crew cost of a Vehicle.

Some Vehicles have abilities that trigger when they become crewed. “Whenever [this Vehicle] becomes crewed” means “Whenever a crew ability of [this Vehicle] resolves.” If that ability has an intervening “if” clause that refers to information about the creatures that crewed it, it means only creatures that were tapped to pay the cost of the crew ability that caused it to trigger.

Doubling a creature’s power and/or toughness creates a continuous effect. This effect modifies that creature’s power and/or toughness but doesn’t set those characteristics to a specific value. See rule 613.4c.

To double a creature’s power, that creature gets +X/+0, where X is that creature’s power as the spell or ability that doubles its power resolves. Similarly, an effect that doubles a creature’s toughness gives it +0/+X, where X is that creature’s toughness. Doubling a creature’s power and toughness gives it +X/+Y, where X is its power and Y is its toughness.

If a creature’s power is less than 0 when it’s doubled, doubling that creature’s power instead means that the creature gets -X/-0, where X is the difference between 0 and its power. Similarly, if its toughness is less than 0 when doubled, it gets -0/-X. If one characteristic’s value is negative but the other isn’t when both are doubled, it gets -X/+Y or +X/-Y, as appropriate.

To double a player’s life total, the player gains or loses an amount of life such that their new life total is twice its current value.

To double the number of a kind of counters on a player or permanent, give that player or permanent as many of those counters as that player or permanent already has.

To double the amount of a type of mana in a player’s mana pool, that player adds an amount of mana of that type equal to the amount they already have.

To double an amount of damage a source would deal, that source instead deals twice that much damage. This is a replacement effect.