Assembled Alphas — ruling 1

The triggered ability deals damage to the creature’s controller even if the creature isn’t dealt damage, perhaps because it has left the battlefield or because the damage was prevented.

Assembled Alphas — ruling 2

The triggered ability triggers once for each creature blocking or blocked by Assembled Alphas. The ability resolves and deals damage to that creature before combat damage is dealt. If that damage destroys all creatures blocking Assembled Alphas, Assembled Alphas doesn’t become unblocked.

Assembled Alphas : règles, fonctionnement et interactions (MTG)

Assembled Alphas 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

Whenever this creature blocks or becomes blocked by a creature, this creature deals 3 damage to that creature and 3 damage to that creature's controller.

How it works : Assembled Alphas

Original English text — Wizards of the Coast / Scryfall

#1July 13, 2016· Wizards of the Coast
The triggered ability deals damage to the creature’s controller even if the creature isn’t dealt damage, perhaps because it has left the battlefield or because the damage was prevented.
No other card is named in this ruling.
#2July 13, 2016· Wizards of the Coast
The triggered ability triggers once for each creature blocking or blocked by Assembled Alphas. The ability resolves and deals damage to that creature before combat damage is dealt. If that damage destroys all creatures blocking Assembled Alphas, Assembled Alphas doesn’t become unblocked.
No other card is named in this ruling.