Here's the deal ... a private art collector in Spain shelled out $1,355 to get a famous painting of the Immaculate Conception -- by Baroque artist Bartolomé Esteban Murillo -- cleaned up by a furniture restorer. Unfortunately, the job was a total botch!!!

The amateur restorer made 2 attempts to fix the art, according to Spain's Europa Press, but as you can see ... it only got worse and worse. We shoulda put a graphic warning on this image for art fans.

The artistic disaster is drawing comparisons to other recent restoration attempts in Spain, where there are no laws governing who is allowed to restore artwork, no matter their skill, or lack thereof.

For example, take this botched 2012 restoration of a prized fresco painting of Jesus Christ by an elderly parishioner of a church near Zaragoza ... she tried to paint over it and now it's infamously known as, "Monkey Christ."

And, just last year, a 16th-Century statue of St. George, which stood at a church in Navarre, drew headlines after an alleged restoration some say looks like a Playmobile figure.

Spain's Professional Association of Restorers and Conservators (ACRE) ripped the country's government in a statement, condemning a lack of restoration regulation and calling the Immaculate Conception incident not a restoration, but a "vandalism."

ACRE says ... "We should be alarmed by the fact that part of our heritage is disappearing due to these disastrous interventions."

To that we say ... Si, si, si!!!