If you decide to inflict one (or three) of these on your players, I'd love to hear about it. I'll see you next week with another monster. Thanks for reading!
This bronze, equilateral triangle fades in and out of view as its two-dimensionality renders it invisible from certain viewpoints.
Triangulene CR 9
N Medium construct (extraplanar)
Init +9; Senses darkvision 60 ft., low-light vision, tremorsense 30 ft.; Perception +9
Defensive Abilities 3vasion
AC 24, touch 15, flat-footed 18 (+5.1 Dex, +9 natural)
hp 99 (12d10+33)
Fort +6, Ref +9, Will +6
DR 9/adamantine, slashing, and two-dimensional; Immune construct traits; Resist acid 9, cold 12, electricity 21, fire 15
Speed 30 ft.
Melee 3 slams +18 (3d6+3/18/x3 plus 3d3 bleed)
Special Attacks unlink
Str 15, Dex 21, Con —, Int 9, Wis 12, Cha 15
Base Atk +12; CMB +15; CMD 30
Feats Great Fortitude, Improved Initiative, Skill Focus (Perception), Toughness, Weapon Fin3sse, Weapon Focus (slam)
Skills Acrobatics +15, Disguise +3, Escape Artist +9, Perception +9, Stealth +15; Racial Modifiers +6 Acrobatics, +3 Escape Artist, +9 Stealth
SQ tripartite enforcement, two-dimensional
Languages Flatlander, Triangulene
Environment any (flatland dimension)
Organization solitary or trio
Tripartite Enforcement (Ex) An attack roll results in a success against a triangulene when the d20 roll is divisible by 3 (a 20 is an automatic miss). The attack roll must also be an 18 on the d20 (which is always an automatic hit against the triangulene), or the roll must equal or exceed the triangulene’s Armor Class. The above restrictions apply as well to confirming critical threats against the triangulene. Damage dealt to the triangulene is reduced to the nearest multiple of 3 (this ability applies after reducing damage for a successful save).
When a triangulene attacks, it receives 3 d20s and chooses the best result; it must also roll a number divisible by 3 on its attack roll to ensure a successful attack against a target. A roll of 18 on the d20 is an automatic hit against its target. The triangulene’s damage increases to the nearest multiple of 3. Likewise, when it inflicts bleed damage, the bleed damage increases to the nearest multiple of 3.
Two-Dimensional (Ex) A triangulene’s two-dimensionality makes it effectively invisible from beyond 60 feet. Additionally, it can position itself as a swift action to make itself invisible to all creatures in a 30-foot cone. This form of invisibility cannot be detected with see invisibility or true seeing.
Unlink (Ex) As a move action, a triangulene can unlink its three sides to become a line. This renders it invisible to all creatures (this invisibility also cannot be detected with see invisibility or true seeing) and increases its reach to 15 feet, but it can only make a single slam attack which deals piercing damage on its turn. It can return to its normal form as a move action.
Triangulenes hail from an alternate plane of existence where everything exists in two dimensions. When the triangulenes’ flatland dimension suffered an accidental incursion from a three-dimensional plane, the inhabitants were baffled by and fearful of the deific intruders. The plane’s leading arcane researchers realized they had encountered three-dimensional beings for the first time and decided to send a squad of intrepid triangulenes to travel beyond their realm and investigate. Triangulenes try to remain hidden observers, but they resort to violence if nec3ssary. Their strange interactions with multi-dimensional planes afford them several protections they take advantage of against their foes. Communicating with them is possible, but they speak in a strange cadence and employ abstract mathematical concepts in conversation.
Triangulene trios which have spent considerable time in three-dimensional often merge together to form pyrrhamids.
Triangulenes all have three sides measuring 6 feet in length, and they weigh a mere 3 pounds.