Can Twinned Spell be used on Plane Shift when it's used to banish an unwilling creature to another plane?

Question

Plane shift has two uses:

• to bring yourself and up to 8 more willing creatures to another plane, or
• to make a melee spell attack against a single unwilling creature, and then force it to make a Charisma saving throw or be brought to another plane

The sorcerer's Twinned Spell metamagic option lets you spend sorcery points to affect two creatures with a spell that normally affects only one.

But here, I'm not sure if the second effect of plane shift is considered eligible for the Twinned Metamagic, because its first effect can indeed affect more than one creature.

Can Twinned Spell be used on plane shift when it's used to banish an unwilling creature to another plane?

Answer 1

No, the errata specifies that spells capable of targetting more than one target do not qualify for twinned spell.

From the errata:

Twinned Spell (p. 102). To be eligible for Twinned Spell, a spell must be incapable of targeting more than one creature at the spell’s current level.

Since part one of the spell can target up to 8 creatures, it's disqualified from being twinned. The option of targetting more is what disqualifies it, which is the same reason you can't twin magic missile if you only target one creature, or eldritch blast when it hits level 5.

Frankly I'd houserule yes if you were just using the 2nd part. But then again I'd also houserule using Magic Missile against one target to be able to be twinned, as well as any other spell that's only hitting one thing. But that's not what the rules say, that's DM privilege.