The Watcher in the Water and Greater Good on the battlefield.
It is not your turn.
You control at least one other creature with power one or greater.
Steps
During an opponent's turn, activate Greater Good by sacrificing another creature with power one or greater.
If the creature was a Tentacle, The Watcher triggers, untapping up to one Kraken you control and putting a stun counter on up to one nonland permanent.
Resolve the Greater Good ability, causing you to draw cards equal to the sacrificed creature's power and then discard three cards.
For each card drawn this way, The Watcher's first ability triggers, creating that many 1/1 Tentacle creature tokens.