Psychic scream causes head exploding if it kills a creature.
Options:
1. They meant "if it reduces the target to 0hp".
2. They meant "if it does enough damage past the creature's current hit points to exceed its maximum hit points".
3. It is either of those, depending on whether the GM causes "monsters" to die at 0hp instead of making death saves, and as such, can be used as a test for is-an-NPC.
4. Other.
I'm currently reading it as 2. Damage is pretty low compared to some other spells (say, meteor swarm), but picking your targets is really nice.
Options:
1. They meant "if it reduces the target to 0hp".
2. They meant "if it does enough damage past the creature's current hit points to exceed its maximum hit points".
3. It is either of those, depending on whether the GM causes "monsters" to die at 0hp instead of making death saves, and as such, can be used as a test for is-an-NPC.
4. Other.
I'm currently reading it as 2. Damage is pretty low compared to some other spells (say, meteor swarm), but picking your targets is really nice.