Shrapnelito

In the windswept wastelands where water is scarce and nothing grows without a fight, the Shrapnelito looks like any other short fruiting cactus. It sits low to the ground, squat and unremarkable, the kind of plant a thirsty traveler might approach without thinking twice. That is the last mistake some of them make.
  Where other cacti store moisture in meaty limbs or broad fronds, the Shrapnelito grows pinecone-like protective plates along its surface, each one studded with spines coated in a waxy irritant. Whiskery tendrils across its surface detect vibration. When something gets too close, the plant draws water from a deep root stem, swelling rapidly until the plates launch outward in an explosive burst. The volley shreds exposed skin and embeds spines into flesh, cloth, and leather with equal indifference. Then the water seeps slowly back into the roots, and the Shrapnelito resets like a loaded trap.
  The spines themselves are only half the problem. That waxy coating is a severe skin irritant, leaving victims covered in itching, rashes, and welts that persist for days. Enterprising souls who have tried to harvest the substance for trade or weaponization are easily identified: they are the ones with raw, blistered arms and swollen faces, scratching themselves bloody while insisting the product is worth the pain.
  A Shrapnelito is unlikely to kill an adult outright. It does not need to. In a wasteland where infection turns minor wounds lethal and clean water is already scarce, a face full of irritant spines is enough to ruin a week and end a journey.