Roborally.com

Yes, it's quite messy. [Since it cannot be dropped on Water, Goo should likewise be prohibited from being dropped on oil.  Flip official answers aside, the ruling "it's quite messy" doesn't help determine if a robot sliding along a long oil slick when it hits Goo should count the remaining oil squares against the limit to remove the Goo, or if the oil will prevent the first movement of a new Move card from being counted against the Goo. -- JHJ]