Reservoir Kraken — ruling 1

Players won't know which player or planeswalker Reservoir Kraken will attack, if any, when deciding whether to tap an untapped creature for its triggered ability.

Reservoir Kraken — ruling 2

Each opponent in turn order may choose to tap an untapped creature as Reservoir Kraken's triggered ability resolves, even if a player earlier in the turn order already chose to tap a creature. Reservoir Kraken's controller will create a maximum of one Fish creature token each combat, no matter how many creatures were tapped.

Reservoir Kraken : règles, fonctionnement et interactions (MTG)

Reservoir Kraken 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

Trample, ward At the beginning of each combat, if this creature is untapped, any opponent may tap an untapped creature they control. If they do, tap this creature and create a 1/1 blue Fish creature token with "This token can't be blocked."

How it works : Reservoir Kraken

Original English text — Wizards of the Coast / Scryfall

#1April 29, 2022· Wizards of the Coast
Players won't know which player or planeswalker Reservoir Kraken will attack, if any, when deciding whether to tap an untapped creature for its triggered ability.
No other card is named in this ruling.
#2April 29, 2022· Wizards of the Coast
Each opponent in turn order may choose to tap an untapped creature as Reservoir Kraken's triggered ability resolves, even if a player earlier in the turn order already chose to tap a creature. Reservoir Kraken's controller will create a maximum of one Fish creature token each combat, no matter how many creatures were tapped.
Card named in this ruling
Fish