Dregscape Sliver — ruling 1

Dregscape Sliver grants the unearth ability to other Sliver cards only while it’s on the battlefield.

Dregscape Sliver — ruling 2

Activating a creature card’s unearth ability isn’t the same as casting the creature spell. The unearth ability is put on the stack, but the creature card is not. Spells and abilities that interact with activated abilities (such as Stifle) will interact with unearth, but spells and abilities that interact with spells (such as Cancel) will not.

Dregscape Sliver — ruling 3

If a creature returned to the battlefield by the unearth ability would leave it for any reason, it’s exiled instead—unless the spell or ability that’s causing the creature to leave the battlefield is actually trying to exile it. In that case, the spell or ability succeeds at exiling the creature. If the spell or ability later returns the creature card to the battlefield (as Astral Drift might, for example), the creature card will return as a new object with no relation to its previous existence. The unearth effect will no longer apply to it.

Dregscape Sliver : règles, fonctionnement et interactions (MTG)

Dregscape Sliver 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

Each Sliver creature card in your graveyard has unearth . Unearth (: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

How it works : Dregscape Sliver

Original English text — Wizards of the Coast / Scryfall

#1June 14, 2019· Wizards of the Coast
Dregscape Sliver grants the unearth ability to other Sliver cards only while it’s on the battlefield.
No other card is named in this ruling.
#2June 14, 2019· Wizards of the Coast
Activating a creature card’s unearth ability isn’t the same as casting the creature spell. The unearth ability is put on the stack, but the creature card is not. Spells and abilities that interact with activated abilities (such as Stifle) will interact with unearth, but spells and abilities that interact with spells (such as Cancel) will not.
No other card is named in this ruling.
#3June 14, 2019· Wizards of the Coast
If a creature returned to the battlefield by the unearth ability would leave it for any reason, it’s exiled instead—unless the spell or ability that’s causing the creature to leave the battlefield is actually trying to exile it. In that case, the spell or ability succeeds at exiling the creature. If the spell or ability later returns the creature card to the battlefield (as Astral Drift might, for example), the creature card will return as a new object with no relation to its previous existence. The unearth effect will no longer apply to it.
No other card is named in this ruling.