You utter a word of power that can compel one creature you can see within range to die instantly. If the creature you choose has 100 hit points or fewer, it dies. Otherwise, the spell has no effect.
I DM’d a group that tried to optimize every situation, and every turn off combat. That’s okay as long as it stays fun, but once they start spinning their wheels, or one player turns combat into a slog, then I take measures.
In my experience (and from what I've heard of other groups) optimisers are rarely the cause of this problem, usually it's the more casual or inexperienced players.
They should have cast speak with animals and made 50 friends