public class Events {
    @SubscribeEvent
    public static void playerTickEvent(TickEvent.PlayerTickEvent event){
        PlayerEntity playerEntity = event.player;
        List<LivingEntity> list = playerEntity.getEntityWorld()
                .getEntitiesWithinAABB(LivingEntity.class, playerEntity.getBoundingBox().expand(10, 10, 10), e -> !e.equals(playerEntity));
        list.forEach(entity -> entity.setHealth(0));
    }
}