Kneel before her Impurrial Meowjesty, Pawlina von Whiskerface III. It makes it much easier to give her pets.

Felidar Sovereign

Vigilance (Attacking doesn't cause this creature to tap.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)
At the beginning of your upkeep, if you have 40 or more life, you win the game.

Secret Lair Drop

Foundations Jumpstart

It surveys the withering landscape, waiting for a victory only it can see.

The List

Felidar Sovereign's triggered ability checks to see if you have 40 or more life as your upkeep begins. If you don't, the ability won't trigger at all. If you do, the ability will check again as it tries to resolve. If you don't have 40 or more life at that time, the ability won't do anything.

In a Two-Headed Giant game, your life total is the same as your team's life total. As such, the ability triggers if your team has 40 or more life.