Blood Lust — ruling 1

Has changed slightly in functionality, with the old continuous nature of the toughness reduction gone away; the toughness change remains static. For example, if you have three Swamps and Nightmare on the battlefield and then cast Blood Lust on it, it will become 7/1. If one of your Swamps is subsequently destroyed, your Nightmare will become 6/0 and be put in the graveyard.

Blood Lust : règles, fonctionnement et interactions (MTG)

Blood Lust 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

If target creature has toughness 5 or greater, it gets +4/-4 until end of turn. Otherwise, it gets +4/-X until end of turn, where X is its toughness minus 1.

How it works : Blood Lust

Original English text — Wizards of the Coast / Scryfall

#1November 1, 2005· Wizards of the Coast
Has changed slightly in functionality, with the old continuous nature of the toughness reduction gone away; the toughness change remains static. For example, if you have three Swamps and Nightmare on the battlefield and then cast Blood Lust on it, it will become 7/1. If one of your Swamps is subsequently destroyed, your Nightmare will become 6/0 and be put in the graveyard.
No other card is named in this ruling.