The literal meaning of SAPO in Spanish is TOAD. But, in Colombia a SAPO can also be a person that is a tattletale, someone who sticks his nose in other people's business, or someone who answers a question when the question wasn't directed at him. The expression is "No Sea Sapo." -- don't be a tattletale or busybody. It can be useful with children -- but note it is strong.
Since it can be rude to call someone a sapo, Colombians have created several humorous expressions that imply that someone is a sapo without having to come right out and actually say that they are a sapo.
Colombians assign to animals certain human characteristics. Then, they use the animals to describe human behavior. Here are other examples:
Loro (parrot) = someone who talks too much
Burro or Mula (donkey or Mule) = someone really stupid
Perro (dog) = a womanizer
Lagarto (lizard) = a person who helps someone in hopes of personal gain
Cabra (goat) = a hyperactive kid
Vaca (cow) = a fat person
Marrano (Pig) = someone who behaves like a pig!