UU Game Terminology - Mandatory

From Unstable Games Wiki

Mandatory effect are effect that MUST be done every single time another effect occurs (if possible), otherwise you cannot play the card, target the card or do an effect.

Mandatory vs. Optional Effects
Some effects are mandatory (ex."DISCARD a card"), while others are optional ("you may STEAL a Unicorn"). If a card does not use the word "may," you can assume it is mandatory.

If a card has an optional effect that states "If this card is in your Stable at the beginning of your turn," you man NOT use that effect if you forget to use it before you DRAW a card for your Draw phase. If the effect is mandatory, you must still do it if you (or another player) notices that you did not use the effect.

IMPOSSIBLE ACTIONS

If you have a card in your hand that requires you to perform an impossible action, you may not play it. Sometimes, however, the effect of a card in your Stable or a card played by any other player may require you to perform an impossible action. If this situation occurs, disregard that action. Some impossible actions include:

Gameplay Terminology