Kircles resembles crabs, more specifically hermit crabs. Their shells, which bizarrely are also their faces, have red and white stripes as well as four yellow spikes, and their big claws have red, yellow and orange stripes.
NiGHTS into Dreams
In NiGHTS into Dreams, Kircles can be found in Spring Valley, Mystic Forest and Stick Canyon. Once either Elliot or Claris enter in one of these Nightopias, two Kircles will steal two of their ideyas. After the Visitors dualize with NiGHTS, the Kircles throughout the levels will try to grab NiGHTS' feet and drag them to the ground. If the Kircles succeed, they will blow up, damaging NiGHTS and making them lose five seconds.
Defeating a Kircle will add 200 points for the player's score.
A Kircle painting also appears on Puffy's mansion during her boss battle.
The Kircle Mepians' head is nearly identical to Kircle's shell faces, being a small striped shell with red and white stripes and four yellow spikes. The Mepians have big and blue colored eyes.
The Torso also resembles Kircle's shell, though this time, the front has a lot of small red and white stripes. The arms and the legs resemble Kircle's orange limbs.
The Kircle Mepians got claws instead of hands, and they are identical to Kircle's, and their feet look like red shoes with an orange stripe.
Curiously, the Kircle Mepians have regular Nightopian wings, thus a Kircle Mepian is the only one in the game that keeps a Nightopian body part.
A Kircle Mepian egg is red with white stripes and spots.
Christmas NiGHTS into Dreams
Kircles appear in the Christmas NiGHTS version of Spring Valley. Once again, the Kircles will steal two of Elliot and Claris ideyas once either enter in the level, and they will try to grab NiGHTS' feet and drag them to the ground. If the Kircles succeed, they will blow up, damaging NiGHTS and making them lose five seconds.
The Kircle Mepian and its egg are identical to their NiGHTS into Dreams' designs.
- NiGHTS Flying Through the Sky Without Wings: A Kircle can be seen during the introduction to Nightmare and when the Nightmarens invade Nightopia. A Kircle icon appears in one of the book's first pages.
- NiGHTS into Dreams (LCD): Kircles appear as enemies in the LCD adaptation of NiGHTS into Dreams. Avoiding them adds 20 points to the game's score
- NiGHTS Archie Comics: A Kircle makes a brief appearance in the second issue, attacking Snuze along with other Nightmarens.
- Sonic Pinball Party: Kircles appear in the Spring Valley table as enemies. Defeating a Kircle adds 200 points to the score.
- Sonic & All-Stars Racing Transformed: Giant Kircles appear in the Dream Valley circuit as obstacles.
- Kircles appear as enemies in the NiGHTS into Dreams shockwave mini game under the name "crabs". Bizarrely, they use Clawz sound files. 
- When a Kircle Mepian is born with a Kircle torso, it will keep the regular Nightopian wings, thus a Kircle Mepian is the only one that keeps a Nightopian body part.
- Kircles are the only Nightmarens who self destruct.
- Kircles were replaced by Mewwys in NiGHTS Journey of Dreams.