The sea wizard curse of the sea says in part:
Once per turn, if you cast a spell, you can trigger the spell if that spell deals cold or lightning damage to the accursed target or forces it to move. If you do so, the target will be subjected to the corresponding additional effect. The curse ends when the spell is not a cantrip (you choose the effect to use when more than one effect is applied):
cold damage, If the affected target suffers cold damage from your spell, the ()
lightning damage, If the affected target suffers lightning damage from your spell, your (…)
forced movement, When the target is moved by your spell, you can (…)
I do not know when The sorcerer actually chooses this ability, because it is different from other features such as: B. the overchannel function of Evokationsassistenten, has unusual formulations.
If you cast a level 5 or lower spell that deals damage, you can use your spell to deal maximum damage.
In the question "When must the assistant decide for an override?" It has been decided that this feature will be used if you speak a magicNot if the spell actually causes damage. However, the Curse of the Sea feature uses a different wording, and I'm not sure how this (if anything) affects the timing of the feature.
Does the sorcerer choose to use this feature while casting the spell or if the spell actually causes movement that causes or forces damage?
Once it matters:
If you have used this feature if you speak a magic and decided to, and then the creature proved immune to cold damage, the extra effect would not occur.