A level clone is a type of level that is common with several custom level sets of Chip's Challenge available on Internet. It's also, unlike the other level themes, one of the most maligned.
To create a "clone", a designer uses the layout of a pre-existing level as a reference, then starts working upon it by modifying it to make it more difficult, or just different, to solve. Interestingly, some levels from Chip's Challenge 1 appear to share several aspects in design or concept, though it's unknown whether or not they were worked with the same maps. For example, both Invincible Champion and Wars include an identical section where bugs surround a cross-shaped chamber with some water and chips, but the former is solved by guiding gliders through the tiles of dirt to the bugs so Chip can force the bugs to die by touching the water and then grab the chips, while the latter refers to the same concept, but with fireballs and without dirt whatsoever (coincidentally, both levels are busted, the former due to an error in the bug formation, and the latter with a block). Another example is Totally Unfair, which has a design that is nearly identical to that of Totally Fair, but the few changes in the tiles are enough to make it significantly more difficult to solve.
For CCLP1, CCLP2 and CCLP3, efforts were made so no level clone was included, but in CCLP2 one managed to make it past the rules. This level is Ranger Denmark, which is a reskinned variation of Lesson 8 from CC1, with various different tiles replacing the more basic ones that built the original. The overlook was probably because, at the time of the set's assembling, the level didn't seem to look like any known level at all. The final level of CCLP3, Mr. McCallahan Presents, contains snippets of various levels from all three official sets, including Special, A Fleeting Memory, and a concept from You Can't Teach an Old Frog New Tricks, but contains enough original content that it was included in the set. An earlier level, Recurring Dream, does the same as part of its concept, and even includes the entire 9x9 area of Vague Dream (of which, in addition, the portion containing the teeth, the blocks and the 2x5 moat is replicated several times in a row in the northern section. Later on, bits and pieces of said Vague Dream area get remixed with different tiles that progressively change the original ones, such as ice in the place of water, force floors in the place of fire, fire in the place of normal floors, etc.).