Scuttling Doom Engine — ruling 1

Once Scuttling Doom Engine has been blocked by a creature, reducing that creature’s power to 2 or less won’t change or undo that block.

Scuttling Doom Engine : règles, fonctionnement et interactions (MTG)

Scuttling Doom Engine 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

This creature can't be blocked by creatures with power 2 or less. When this creature dies, it deals 6 damage to target opponent or planeswalker.

How it works : Scuttling Doom Engine

Original English text — Wizards of the Coast / Scryfall

#1July 18, 2014· Wizards of the Coast
Once Scuttling Doom Engine has been blocked by a creature, reducing that creature’s power to 2 or less won’t change or undo that block.
No other card is named in this ruling.