Real Madrid s Vinicius Junior, right, and Athletic Bilbao s Mikel Vesga challenge for the ball during the Spanish La Liga soccer match between Athletic Club Bilbao and Real Madrid at the San Mames stadium in Bilbao, Spain, Sunday, Jan. 22, 2023. AP
"Madrid hates Real," read a banner draped on the bridge close to Valdebebas overnight Wednesday.
The Vinicius effigy was described as a "disgusting act of racism, xenophobia and hatred" against the Brazilian forward, by Real Madrid in a statement.
"Attacks like those our player is suffering now, or those that any athlete can suffer, cannot have a place in a society like ours," added Madrid.
Police sources told AFP they were investigating the incident, without offering further details.
The slogan is one which has been used by Atletico Madrid ultras in the past.
"Such acts are absolutely repugnant and inadmissible and shame society," said Atletico in a statement.
"Our condemnation of any act that attacks the dignity of persons or institutions is categorical and unreserved."
Atletico fans were filmed aiming racist chants at Vinicius in September before the Madrid derby at the Wanda Metropolitano in La Liga.
However in December Spanish prosecutors closed an investigation into the chants, saying it was not possible to identify those culpable.
"We condemn the hateful actions against Vinicius," wrote La Liga on Twitter.
"Intolerance and violence do not fit within football."
The Spanish football federation (RFEF) also offered their support to Vinicius, describing the incident a direct threat aimed at the forward "loaded with hate".
Real Madrid's 22-year-old winger is a divisive figure in Spanish football, with opponents sometimes angered by his flair and playing style, his propensity to go to ground easily and dancing goal celebrations.
On the other hand, Vinicius is often targeted and hacked by opposition defenders to try and put him off his game, with no player in Europe fouled more this season.
"We have to protect him," urged Real Madrid coach Carlo Ancelotti on Wednesday in a news conference.
"Football needs him, he's got an extraordinary talent and we have to protect him physically and in a mental aspect too."
Real Madrid host rivals Atletico at the Santiago Bernabeu later on Thursday.