When is a player considered 'poisoned' in a Two-Headed Giant game?

In a Two-Headed Giant game, the concept of being 'poisoned' refers specifically to the status of the entire team rather than individual players. A player is considered 'poisoned' when their team collectively has one or more poison counters. This means that the poisoning effect applies to both players on the team, and it is the team’s total poison counter count that matters in this format.

Due to the nature of how Two-Headed Giant operates, players work together, and their health, poison counters, and overall game state are shared. Therefore, if either member of the team has poison counters, it directly influences both players' statuses, effectively making them 'poisoned'.

The other options do not capture this team-oriented rule specific to Two-Headed Giant play. Individual players having poison counters does not reflect the collaborative aspect of the format, nor does simply losing life from poison effects or a partner having poison counters indicate that the player themselves is considered 'poisoned'. Therefore, the correct description encompasses the essence of teamwork in this game mode.