Junk Jet

When this Equipment enters, create a Junk token. (It's an artifact with "{T}, Sacrifice this token: Exile the top card of your library. You may play that card this turn. Activate only as a sorcery.")
{3}, Sacrifice another artifact: Double equipped creature's power until end of turn.
Equip {1}

Fallout

When Junk Jet enters the battlefield, create a Junk token. (It's an artifact with "{T}, Sacrifice this artifact: Exile the top card of your library. You may play that card this turn. Activate only as a sorcery.")
{3}, Sacrifice another artifact: Double equipped creature's power until end of turn.
Equip {1}

When Junk Jet enters the battlefield, create a Junk token.
{3}, Sacrifice another artifact: Double equipped creature's power until end of turn.
Equip {1}

If a creature's power is less than 0 when it's doubled, instead that creature gets -X/-0, where X is how much less than 0 its power is. For example, suppose you control Infesting Radroach, a 2/2 creature. If an effect has given Infesting Radroach -4/-0 so that it's a -2/2 creature, doubling its power gives it -2/-0, and it becomes a -4/2 creature.

If an effect instructs you to "double" a creature's power, that creature gets +X/+0, where X is its power as that effect begins to apply.

If you "double" a creature's power more than once in a turn, each doubling effect applies independently. For example, suppose Junk Jet is attached to Infesting Radroach, a 2/2 creature. If you activate Junk Jet's second ability, Infesting Radroach will get +2/+0 when that ability resolves, making it a 4/2 creature. Doubling its power again will give it +4/+0, making it an 8/2 creature.

Some spells and abilities that create Junk tokens may require targets. If each target chosen is illegal as that spell or ability tries to resolve, it won't resolve and none of its effects happen. You won't create any Junk tokens.

You can't sacrifice a Junk token to pay multiple costs. For example, you can't sacrifice a Junk token to activate its own ability and also to activate the second ability of Junk Jet.

You pay all costs and follow all normal timing rules for the card played from exile with a Junk token's ability. For example, if the exiled card is a land card, you may play it only during your main phase while the stack is empty.

Junk

{T}, Sacrifice this artifact: Exile the top card of your library. You may play that card this turn. Activate only as a sorcery.