Vengeful Pharaoh — ruling 1

Vengeful Pharaoh must be in your graveyard when combat damage is dealt to you or a planeswalker you control in order for its ability to trigger. That is, it can't die and trigger from your graveyard during the same combat damage step.

Vengeful Pharaoh — ruling 2

If Vengeful Pharaoh is no longer in your graveyard when the triggered ability would resolve, the triggered ability won't do anything.

Vengeful Pharaoh — ruling 3

If the attacking creature is an illegal target when the triggered ability tries to resolve, it won't resolve and none of its effects will happen. Vengeful Pharaoh will remain in your graveyard.

Vengeful Pharaoh — ruling 4

If multiple creatures deal combat damage to you simultaneously, Vengeful Pharaoh will only trigger once.

Vengeful Pharaoh — ruling 5

If multiple creatures deal combat damage to you and to a planeswalker you control simultaneously, Vengeful Pharaoh will trigger twice. The first trigger will cause Vengeful Pharaoh to be put on top of your library. The second trigger will then do nothing, as Vengeful Pharaoh is no longer in your graveyard when it tries to resolve. Note that the second trigger will do nothing even if Vengeful Pharaoh is put back into your graveyard before it tries to resolve, as it's a different Vengeful Pharaoh than the one that was there before.

Vengeful Pharaoh — ruling 6

If your own attacking creatures deal combat damage to you or a planeswalker you control (perhaps because combat damage was redirected), Vengeful Pharaoh will still trigger. You must target and destroy one of your own attacking creatures.

Vengeful Pharaoh : règles, fonctionnement et interactions (MTG)

Vengeful Pharaoh 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

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.) Whenever combat damage is dealt to you or a planeswalker you control, if this card is in your graveyard, destroy target attacking creature, then put this card on top of your library.

How it works : Vengeful Pharaoh

Original English text — Wizards of the Coast / Scryfall

#1September 22, 2011· Wizards of the Coast
Vengeful Pharaoh must be in your graveyard when combat damage is dealt to you or a planeswalker you control in order for its ability to trigger. That is, it can't die and trigger from your graveyard during the same combat damage step.
No other card is named in this ruling.
#2September 22, 2011· Wizards of the Coast
If Vengeful Pharaoh is no longer in your graveyard when the triggered ability would resolve, the triggered ability won't do anything.
No other card is named in this ruling.
#3September 22, 2011· Wizards of the Coast
If the attacking creature is an illegal target when the triggered ability tries to resolve, it won't resolve and none of its effects will happen. Vengeful Pharaoh will remain in your graveyard.
No other card is named in this ruling.
#4September 22, 2011· Wizards of the Coast
If multiple creatures deal combat damage to you simultaneously, Vengeful Pharaoh will only trigger once.
No other card is named in this ruling.
#5September 22, 2011· Wizards of the Coast
If multiple creatures deal combat damage to you and to a planeswalker you control simultaneously, Vengeful Pharaoh will trigger twice. The first trigger will cause Vengeful Pharaoh to be put on top of your library. The second trigger will then do nothing, as Vengeful Pharaoh is no longer in your graveyard when it tries to resolve. Note that the second trigger will do nothing even if Vengeful Pharaoh is put back into your graveyard before it tries to resolve, as it's a different Vengeful Pharaoh than the one that was there before.
No other card is named in this ruling.
#6September 22, 2011· Wizards of the Coast
If your own attacking creatures deal combat damage to you or a planeswalker you control (perhaps because combat damage was redirected), Vengeful Pharaoh will still trigger. You must target and destroy one of your own attacking creatures.
No other card is named in this ruling.