* In ''TabletopGame/{{Warhammer}}'' and ''TabletopGame/{{Warhammer 40000}}'':
** Warriors of Chaos can be blessed or cursed with "gifts" from their patron Gods, turning them steadily more inhuman. Eventually, at a certain point, the weak-willed become mindless Chaos Spawn, while those with [[HeroicWillpower Villainous Willpower]] ascend into Daemon Princes who retain their sentience and control over their vast powers. In either case the warrior now becomes a full Daemon extra vulnerable to anti-Daemon abilities and armament.
** In previous editions of 40K, Greater Daemons aligned with Chaos Space Marines do not appear with the rest of the army, but must be summoned into combat. This involves the sacrifice of a champion. This actually allows you to initiate a One-Winged Angel transformation mid-game, as the Daemon will always be considerably more powerful than whatever hapless shlep it used to be.
* ''TabletopGame/CthulhuTech'':
** Dhohanoids are {{Half Human Hybrid}}s that can change between a human form and a monstrous one.
** Tagers are able to do this too... but in keeping with the fact that they're ''[[DarkIsNotEvil good guys]]'', their OneWingedAngel is a bit more streamlined [[TransformationTrauma than that of Dhohanoids]].
** Nyarlathotep tends to do this in mythos {{RPG}}s. Destroying his human form often causes him to manifest as some kinds of sanity-blasting monstrosity.
* TabletopGame/{{GURPS}} alows a player to build their own version with the alternate form advantage.
* ''TabletopGame/DungeonsAndDragons'':
** Ragnorra, the obligatory BodyHorror entry from ''Elder Evils'', transforms from a bloated blob of wormlike flesh into a curiously human face made out of strands - her True Mother form. While spawning utterly abhorrent monstrosities that simply should not be.
** Averted with [[GodOfEvil Asmodeus]]: While his true form is apparently a giant primordial serpent of some sort, the rules given for fighting him - as unlikely a situation it would be to fight the super-intelligent, scheming ruler of all {{Hell}} - only describe fighting him in his humanoid devil form. (Presumably because, against a being to whom the word "god" would be an ''insult'', your party wouldn't stand a chance.)
** Played straight with Lolth, the evil goddess of the drow, who's infamous One-Winged Angel form - that of a half-drow-half-spider - has been well-known since the ''First Edition''. Most recently, in the Fourth Edition's ''Monster Manual 3'' (where she received updated stats ''and'' appeared on the cover) far greater detail was given on how she transformed. (If reduced to zero hit points in her drow form, she turns into her One-Winged Angel form automatically, where she's stronger, and much, ''much'' more dangerous than before.)
* Erwin Stahler from ''TabletopGame/MutantChronicles'' starts out as a human-sized model on the battlefield, but once he's down, he goes OneWingedAngel and turns into a bigger, armored mutant with big honking claws.
* ''TabletopGame/{{Exalted}}'' just loves this trope.
** Lunar ''Deadly Beastman Transformation'', or ''Warform'', allows them to transform into a nine-feet tall monstrous merge of their animal and human forms. It comes with increase to physical parameters, host of mutations to represent the alterations and ability to instantly activate a wide array of complementary Charms to buff themselves up higher. And even if you can deal with all that and beat it down to a point when every other Exalt would lie on the ground and helplessly bleed out to death? The Lunar does not bleed. The Lunar '''regenerates''' and will get up for a round two if you turn your back on the body.
** Several Lunar Knacks serve to enhance their forms further, letting them grow their animal form or warform to {{Kaiju}} comparable sizes and go a-stomping.
** Infernals have Shintai charms which let them change into a monstrous form based on the Yozi the power is derived from. The most minor ones for physical changes turn you into a version of you crafted from red mist (''Scarlet Rapture'') or sand (''Soul-Sand Devil''), can split off a mortal clone of you (''Splintered Gale''), or allow you to copy someone else (''Black Mirror''). More extreme ones give you a constellation of crystalline orbs (''Heuristic Logos''). The most one-winged of them are ''Tenebrous Apotheosis'' (which ramps you up to become the Ebon Dragon), ''All-Devouring Depths'' (which turns you into a shoggoth), ''Demon Emperor'' (which turns you into [[FantasticNuke a walking Ground Zero]]), ''Greater Shintai of the Endless Desert'' (which turns you into a [[GeniusLoci living geographical feature]]) and ''Devil-Tyrant Avatar'' (which allows you to string together mutations to build your own form). Of these, only Soul-Sand Devil and Splintered Gale can't be used as a rude surprise in combat, and that's only because one is permanently in effect and the other is used to create ''mortals'', although one odd Splintered Gale build theoretically allows you to mass-produce cloned suicide bombers.\\
In the upcoming third edition of the game, the system gets revamped to allow you mix and match the pieces (which you get by buying other Charms) to create your own Shintai.
** The Shintai Charms are augmented by the Charm Driven Beyond Death. When an Infernal hits the Incapacitated Health Level, they make like they're downed (like, say, going down on one knee). Then their [[PowerGlows anima banner]] erupts, and they have one turn where they're completely untouchable but can only activate a Shintai Charm. At that point, they reenter battle with their [[{{Mana}} Essence]] pool somewhat refreshed... and at the end of the battle, they have to roll not to keel over regardless.
** Even Sidereals get into this: they turn their Familiars or mortal acquaintances into massive Elemental Dragons which they can ride. Unfortunately, this destroys the personality of the pet and reduces them to a vegetative state when it's over unless the Sidereal sacrifices a dot of permanent Willpower to let them live on in their Dragon form.
** The errata document for 2e includes an upgrade to the stats of the Unconquered Sun as he appears in the ''Glories of the Most High'' supplement that gives him an enhanced form called ''Magnanimous Unbound Sun'' that gives him an extra couple hundred health levels, an extra 28 arms, constant regeneration, and the inability to be killed unless this enhanced form can be dealt with.
** There are Sorcery spells available to all Exalt types: ''Incomparable Body Arsenal'' turns the caster into a mechanical creature, sprouting weapons out of anywhere, while ''Invulnerable Skin of Bronze'' can complement that with increased defences.
** On the high end, there is a powerful necromantic spell, ''Birth of Sanity's Sorrow''. It activates at the moment of the necromancer's death, and transforms their dying corpse into a titanic monstrosity of grotesque design, inspired by the necromancer's delusions and nightmares of dead principles. Fortunately, [[FunWithAcronyms BoSS]] is usually only accessible to very high level Abyssals and their Deathlord masters.
** On the Martial Arts front, the capstone Charm of ''Dreaming Pearl Courtesan Style'' turns you into a kind of gazelle/carp hybrid abomination made out of dreams (or nightmares). This transformation can last indefinitely, but is addictive and hard to turn off, while abuse may lead to you getting dissolved into the world of dreams.
** On the Blossom of Perfected Lotus, the Sidereal Martial Arts (it is noted that the previous entry is touching on that level), a couple of Styles are worthy of note here. From ''Prismatic Arrangement of Creation Style'', ''Four Magical Materials Form'' turns you into a living Artefact with huge boosts all around (and even more if you use the ''Prismatic Arrangement of Creation Form'' capstone to combine it with other MA forms). Meanwhile, ''Beauty in the Eye'', from ''Border of Kaleidoscopic Logic Style'', has you vanish for a turn and return with an explosion, transformed into a titanic figure modelled after the deity that granted your Exaltation and shaped from elemental substance most prevalent in the region.
** ''Shards of the Exalted Dream'' has Burn Legend, which reimagines Exalted as a kind of VideoGame/{{Tekken}} kung fu brawl setting. The [[LimitBreak Overdrive]] for [[LikeABadassOutOfHell Yamajin]], known as ''Demon Emperor Shintai'' but bearing no similarities with the one described above, causes you to take on a monstrous form and get +3 to all your stats until you lose a health stock. Generally speaking, if a Yamajin gets up to Demon Emperor Shintai, the rest of the fight will not go well for the other player unless they get ''incredibly'' lucky or [[TacticalRockPaperScissors can predict what attack the big guy is about to use]].
* ''TabletopGame/DemonTheFallen'' gives the titular Fallen "apocalyptic forms," echoes of their glory from when they served Heaven. Each form is based off of a primal incarnation of the Lores the angel knows; therefore, a Devil in the mold of Lucifer could have an apocalyptic form that's either a pillar of fire or a glorious, shining light, and a [[BeastMan Devourer]] could have an apocalyptic form that's either a man with the head of a lion or the perfection of human flesh made manifest. But if the demon's weighed down by [[ThisIsYourBrainOnEvil Torment]], well... expect the apocalyptic form to look honked up.
** [[TabletopGame/VampireTheMasquerade Vampires]] have access to some nasty disciplines that let them do this, such as Zulo Form of Vicissitude, the armor of living shadow of [[CastingAShadow Obtenebration]], the War Form of [[VoluntaryShapeshifting Protean]] and [[ScaledUp Serpentis]].
** The aforementioned Shintai charms first appeared in ''TabletopGame/KindredOfTheEast'', as SupernaturalMartialArts that [[ChineseVampire Kuei-Jin]] can learn. All of them turn their user into a horrid, no-nonsense monstrosity when activated. And yes, it had a Demon Emperor Shintai, which is your SuperpoweredEvilSide made manifest.
* The Unchained of ''TabletopGame/DemonTheDescent'', the TabletopGame/NewWorldOfDarkness's analogues to the Fallen, can change into their true demonic forms, which tend towards biomechanical horror, befitting their status as former servants of the [[DeusEstMachina God-Machine]]. It's also possible for a demon in dire circumstances to "[[DangerousForbiddenTechnique go loud]]", assuming their demonic form at full power with a healthy store of [[{{Mana}} Aether]]; however, it irrevocably rips their mortal identity apart, meaning they're now a big glowing beacon for all their divine enemies.
* The [=nWOD's=] [[TabletopGame/WerewolfTheForsaken Werewolves]] have access to a nightmare warform.
** So do all the werecreatures of TabletopGame/WerewolfTheApocalypse, mostly a huge anthropomorphic animal creature like a three-metre tall wolf-man. And then there's the Mokole, the lizard keepers of Gaia's memory. What's the warform of a race of crocodiles, gila monsters and assorted reptiles? Why, your very own dragon/dinosaur/kaiju-lookalike, individualized for every character by a list of traits including "razor claws", "poison sacs", "huge size" or "wings". They dream up their form from ages past - and some of those dreams can be [[MixAndMatchCritters pretty weird indeed]].
* The NeoPets' web-based RPG parody/thingy ''Neo Quest II'' has the final boss "defeated", then returning with a few additional immunities, double the HP, and a double-sized graphic. And additional limbs, wings, spikes, and menace.
* Omega -an [[CaptainErsatz Ersatz]]/{{Expy}} of FinalFantasy bosses- in AnimaBeyondFantasy qualifies, with three different forms, the latter ones nastier and more powerful than the former ones.