Spanish customs officials say in recent years they have found cocaine in breast implants, a wig and even a plaster cast encasing a man's broken leg.
Spain is seen as the main entry point in Europe for drug smugglers from South America.
Argentina says it has foiled a plan to produce and ship liquid cocaine to the United States and Europe.
At least eight people are suspected of having sent two tonnes of the drug, mixed with insulating oil inside large transformers, to Mexico.
A Mexican chemist and several Argentine police officers are among the arrested, Argentine Security Minister Sergio Berni told reporters.
It was the second seizure of liquid cocaine in Argentina this year.
Police suspect this type of trafficking is on the rise, the Argentine media reported.
In February, liquid cocaine was found hidden in a tanker lorry.
The transformers made it through customs controls in Argentina and in Mexico, Mr Berni said.
But on closer inspection, a team of Argentine investigators who had been on the gang's trail since 2012 found the drugs.
The shipment, seized in the Yucatan Peninsula two weeks ago, had a reported street value of $40m (£24m).
From Mexico, the drugs would allegedly be smuggled into the US and Europe.
The authorities also seized computers, weapons and cash, Mr Berni told a news conference in Buenos Aires.
"The important thing is to investigate, to not be afraid, to show courage like this judge did," Mr Berni praised the investigating judge in charge of the case, Sandra Arroyo Salgado.
On 22 April, a Mexican chemist was arrested in the Buenos Aires district of Belgrano after a shootout with the police.
Mr Berni said Cesar Cornejo traveled to Argentina after his partners – most of them serving and former policemen – procured enough cocaine in other South American countries.
The drug was then mixed with insulating oil and hidden in transformers.