Remorhaz

An immense centipede-like beast erupts from the snow, rows of chitinous plates on its back glowing red-hot.

Source: Dungeons & Dragons Monster Manual 5th Edition

     Living in glaciers or the tundra of the north. Laying silent in their carved out warrens created by their intense heat the Remorhaz wait. A sudden vibration in the snow and ice above springs this creature into action. With a sudden explosion of ice beneath your feet this fearsome arctic predators burst forth from the ground. With one intent to have you as dinner.

     Remorhaz are found in arctic climate. Generally feeding on local prey like elk and polar bears. Their bodies generate intense heat that let's them create mazes of tunnels beneath the ice and snow. When waiting for prey they can lower their body temperature so it doesn't melt it's cover. They are cunning predator with low intelligence but can understand the giant tongue and at times controlled by the local frost giant tribes.

     Remorhaz are huge creatures. Typically being 25 feet long and weighing 10,000 pounds. This mid-level challenge employ a vicious bite and ability to eat their prey whole.

Combat: Remorhaz is a huge monstrosity with a challenge rating of 11.

-Movement: 30ft, Burrow 20ft

-Damage Immunities: Cold & Fire

-Senses: Darkvision 60ft, Tremorsense 60ft, and a Passive Perception of 10.

-Bite: +11 to bite with a 10ft reach. If hit by a bite attack the victim takes 6d10+7 points of damage plus 3d6 of fire damage. If a target is hit it is grappled. A DC 17 escape check to get out.

-Swallow Whole: The Remorhaz can make a bite attempt at the victim it is grappling. If the attack hits the victim takes the bite damage and is swallowed whole. While swallowed the victim is blinded and restrained. While inside the Remorhaz the victim takes 6d6 acid damage at the start of each of the Remorhaz turns. If the Remorhaz takes 30 or more damage on a single turn from inside it's body it must make a DC 15 Constitution saving throw or regurgitate the contents of it's stomach.

     The Remorhaz makes for a great random encounter while travelling through an arctic climate. They are the perfect ambush predator. With a massive amount of damage from their bite attack and the ability to eat your players characters whole makes an encounter with a Remorhaz quite deadly. Add in environmental hazard of the frigid cold and you can have a perilous situation on your hands.
 

Nothic

This hunched creature has a single huge eye that dominates its entire face. Its body is bloated and misshappen, and its limbs are wiry but strong, Its arms end in claws that reach the ground as it moves in awkward hop.

Source: Miniatures Handbook 3.5
D&D Monster Manual 5E

     Nothic are aberrations that live in underground lairs and ruins. Rumor has it that wizards who dabble in the arcane secrets are transformed into a Nothic when a rituals goes wrong. The Nothic retain no memory of their former selves. They do have an urge to seek out magic. They can be encountered lurking in cellars of the local arcane academy or ruins of a great wizards tower.
     The Nothic seek forbidden lore and knowledge. They covet magic items and will easily accept them as payment for lore they may possess. The Nothic hope that one day their desire for magical secrets will revert their condition.


Combat: In D&D 3.5 the Nothic is a CR 3 creature. It has relatively high hit points that average out at 42. They have two claw attacks that deal 1d4+4 damage.

-Flesh Rotting Gaze: Anyone who see a Nothic within 30ft must make a Will Save 16 or take 1d6 points of damage.

-Sight: Nothic can see invisibility and have darkvision 120ft.

In D&D 5E the Nothic is a Challenge Rating of 2. It has 45 hit points, Armor Class of 15, and two claw attacks that deal 1d6+3 damage.

Rotting Gaze: The Nothic can target one creature with it's gaze within 30ft. The victim must make a DC 12 Constitution Saving Throw or take 3d6 necrotic damage.

Weird Insight: The Nothic can target a creature within 30ft to steal a piece of knowledge from them. It's a contest between the victims Charisma(Deception) vs the Nothics Wisdom(Insight). Failure allows that Nothic to steal one fact or secret from the victim.

The Miniatures Handbook version is pretty sparse about the Nothic. It mentions nothing about their arcane past and has them as simple subterranean lurkers. The D&D 5E Monster Manual gives them some backstory and depth. I like the Weird Insight ability of the Nothic for 5E. Stealing a Secret from a prominent NPC can lead to an interesting sidetrek.