From the name, I thought this would be something like "~ ETBs as a copy of any creature on the battlefield, except it has toughness 1".

Yeah it doesn't really seem like there's much connection between flavor and mechanics on this card.

So the "When ~ ETBs", draw a card." was added because the design needed something else, and cantripping is fairly neutral.
I wondered how to interpret making a colorless mana for this set, or I was trying to do something with drawn or painted art. One of the two, I don't remember. Then I remembered the following point of carnivalesque: "Profanation: in carnival, the strict rules of piety and respect for official notions of the 'sacred' are stripped of their power — blasphemy, obscenity, debasings, 'bringings down to earth', celebration rather than condemnation of the earthly and body-based." And I thought the idea of a caricature, an image twisting and making the original grotesque could be viewed as distant enough like a card having a color identity, but when viewed as a caricature, only the most-basic part, the colorless part, can participate in representation.

Of course that whole scenario is based on the idea that spells have color and doesn't make sense when adjacent or involved with the Eldrazi.