What's your favorite weird or even kinda lame D&D monster? I like grabgrass from BECMI.
I don't think there's been a more humble origin than the flumph, introduced in the 1981 Fiend Folio as a hovering jellyfish that floated around defending itself as needed. But later publications turned it into an interesting and useful part of the Underdark ecosystem. It detects strong positive and negative emotions and changes its own colors to reflect its mood, making it a valuable companion that can sense the approach of violent monsters with ill intent.
[The algoid is a Fiend Folio monster with interesting abilities but no clear world building hook. Why does algae assemble into a humanoid form? Why does it attack people? Why is it chaotic neutral as opposed to any other alignment? Why does it have psychic powers? The 2e version doesn't address those questions, which might be why the algoid morphed into the vine horror in 3e and became one of the blights of 4e onward. Those at least are solidly evil and hate people, so have a reason to attack adventurers. I'm going back to the original and tying it into some of Paizo's occult concepts, and downplaying its ability to animate plants a bit. The 1e algoid can animate trees with the strength of a treant. That's a very powerful ability on a treant, let alone a monster with half the Hit Dice. That is one of the things I like about 5e's approach to monsters; giving animated trees their own, and much weaker than a full treant, stat block.
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Algoid
CR 5 CN Plant
This green humanoid figure has underdeveloped features with little more than a pair of eyes and a suggestion of a face. Its arms and legs widen towards the hands and feet, as if it is difficult to keep them solid.
When ley lines pass through swampy environments, their occult energy can resonate inside one of the most mundane of all organisms: pond scum. Algoids spend most of their lives discorporated into a mass of algae and water plants, peacefully photosynthesizing and absorbing nutrients. If creatures attempt to eat them or drain the water in which they dwell, or if another creature attempts to tap into the power of their ley line, the algoids will rouse themselves to attack. Algoids can animate mundane plants to strike at enemies and stun creatures with pulses of occult might, but their most dependable tactic is simply to lash out with blobby fists. Algoids are sodden with water, which protects them from energy and physical attacks alike, but renders them vulnerable to spells and effects that manipulate water.
Algoids are not evil and can be negotiated with, but they are also quite stupid and have simple needs. A creature wishing to attune itself to a ley line without angering its algoid denizens may be able to assuage them by offering up interesting trace nutrients or by killing or driving away a particularly obstinate herbivore. Algoids communicate through telepathy, typically simple phrases like “go away”, “kill elephant” or “sunny days good”. They can also communicate with mundane plant life in their habitats, and sometimes have bits of gossip to share, although they are much more interested in weather patterns and soil quality than the concerns of humanoids.
Algoid CR 5
XP 1,600
CN Medium plant
Init +0 (+4 when ending discorporation); Senses darkvision 60 ft., Perception +8
Defense
AC 18, touch 10, flat-footed 18 (+8 natural)
hp 57 (6d8+30)
Fort +9, Ref +2, Will +4
DR 10/magic or bludgeoning; Immune critical hits, electricity, fire, plant traits, sneak attacks
Weakness aqueous
Offense
Speed 20 ft., swim 30 ft.
Melee 2 slams +9 (1d10+4)
Psychic Magic CL 5th, concentration +8 (+12 defensively)
9 PE—speak with plants (3 PE), synaptic pulse (3 PE, DC 16), wilderness soldiers (2 PE)
Statistics
Str 18, Dex 11, Con 19, Int 4, Wis 15, Cha 16
Base Atk +4; CMB +7; CMD 17
Feats Combat Casting, Toughness, Weapon Focus (slam)
Skills Disguise +6 (+21 when discorporated), Perception +8, Swim +12
Languages telepathy 30 ft.
SQ discorporate
Ecology
Environment any marshes
Organization solitary or bloom (2-6)
Treasure incidental
Special Abilities
Aqueous (Ex) An algoid takes 1d6 points of damage per caster level if subject to a control water spell (maximum 10d6, no save). It is treated as being a water elemental for the purpose of dust of dryness.Discorporate (Su) As an immediate action, an algoid can relax the supernatural energies that bind together its form, causing it to seem to fall apart into a patch of pond scum. While discorporated, an algoid gains a +16 racial bonus on Disguise checks to appear as mundane algae. Any attempt to disperse or scatter the algae immediately ends the disguise. A discorporated algoid cannot move or attack, but can use its psychic magic and can return to its normal shape as a swift action—if it does so in the same round it rolls initiative, it gains a +4 racial bonus on its initiative check.
I'm seeing some reports that the fantasy artist Emmanuel just passed away. One of the artists who helped hone the look of Advanced Dungeons & Dragons, I was especially a fan of his cover for the Fiend Folio, which I consider one of the sacred texts of AD&D. One of the many guides I used to check out from the library and draw monsters from.
