mot·tle 
(mŏtl)
(mŏtl)tr.v. mot·tled, mot·tling, mot·tles
To mark with spots or blotches of different shades or colors.
n.
1. A spot or blotch of color.
2. A variegated pattern, as on marble.
[Probably back-formation from MOTLEY.]
mottler n.