Is your party outnumbered? Low on armour? Confined to a narrow passage? No worries, mate! Just roll out this camouflaged welcome mat, and let your foes take care of themselves!
Shape a piece of ground into hard spikes. A creature walking on the spikes takes 2d4 piercing damage for every 1.5 m / 5 ft it moves.
The diminutive die in that description might look laughable at first glance, but consider how large the spiked area is: 40 ft diameter, meaning 16d4 or an average of 40 damage to anything that crosses its full width. All those tetra-dice sure are pointy!
The area is wider than a typical humanoid's movement per turn, so most things without wings won't have time to do much after crossing it.
On top of that:
The spikes are difficult terrain, halving a creature's movement speed.
So, while waiting for the baddies to slog through the brambles, you can pass the time with target practice on their ranged-attack buddies.
What's that you say? Your visitors somehow made it across, and are now breathing down your neck and twice as pissed off? Perfect! Now's the time to practice your thunderwave, or favorite knock-back ability, or turn undead if the neighbours are necrotic, or just give them a good old fashioned shove, and let them enjoy your garden tour all over again.
Wait a minute! You're facing a threat of higher intelligence and refined poise, and they stopped before stepping on your grass? What a great time for your druid to yoink them out of their comfort zone with a thorn whip, or (if you earned it as a reward) try out Sorrow's similar spell.
Did your barbarian charge in before you could seed the field? Ask her to toss a body or two onto the flower bed while they're still standing. They make great compost!
In short, wizards and sorcerers might love to talk about their fireballs, but with this horticultural marvel, my bard has more fun. All natural, certified organic, and (as a level 2 spell) cheap and easy.
Happy plowing!
That's been my experience, too. I much enjoyed reading this and it would theoretically be just as much of a favorite spell, but I've only actually used it to real effect twice. Usually they just jump over it, so I stopped bothering to use it in favor of reliable fun like Call Lightning. I hadn't gotten a good reason to use Hunger of Hadar yet, and I'm disappointed to hear the same. Not really surprised.
Tbf, it IS technically one of the things that make combat so interesting/stressful. There is little you can do that they can't also do back and I'm not even going to complain about the time they pushed me down in my own spikes. Thinking nothing I'm facing is going to have the brainpower to avoid or use the same terrain is my own miscalculation.
But it is less fun. This may be another of the things I chalk up to the subtle split between what RPers expect going in (clever tactical planning) vs. what gamers expect (to dominate the field bc I'm the protagonist). Mixing the two groups has been interesting to watch