Rakdos, the Showstopper — ruling 1

Players can't take any action between the time that coins are flipped and the time creatures are destroyed. For example, if they wish to cast a spell to have a creature gain indestructible, they must do so before Rakdos's triggered ability resolves, without knowing whether that creature's coin will come up heads or tails.

Rakdos, the Showstopper — ruling 2

All of the creatures whose coins come up tails are destroyed at the same time.

Rakdos, the Showstopper : règles, fonctionnement et interactions (MTG)

Rakdos, the Showstopper 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

Flying, trample When Rakdos enters, flip a coin for each creature that isn't a Demon, Devil, or Imp. Destroy each creature whose coin comes up tails.

How it works : Rakdos, the Showstopper

Original English text — Wizards of the Coast / Scryfall

#1January 25, 2019· Wizards of the Coast
Players can't take any action between the time that coins are flipped and the time creatures are destroyed. For example, if they wish to cast a spell to have a creature gain indestructible, they must do so before Rakdos's triggered ability resolves, without knowing whether that creature's coin will come up heads or tails.
No other card is named in this ruling.
#2January 25, 2019· Wizards of the Coast
All of the creatures whose coins come up tails are destroyed at the same time.
No other card is named in this ruling.