Mel Gibson Accused of Pastry Meltdown!

Mel Gibson allegedly tried to run over a man outside a Costa Rican bakery ... but at least one eyewitness tells TMZ the man's a liar.

Quick backstory -- Nader Sharif sued Mel, claiming the actor swindled him out of $200,000 by cajoling him into investing in a recyclable rubber company.

Sharif filed a lawsuit in June, but he's filing new documents today, in which he claims Mel tried to mow him down in July, after the two ran into each other at a Costa Rican bakery.

Sharif says Mel got violent, calling him "vile and offensive names" and threatening him with physical harm if he didn't skip town.

Sharif alleges Mel stormed out of the bakery and got into his car. Sharif says he left the premises moments later, and Mel "accelerated the car to a high rate of speed" and drove the car directly at him while multitasking by giving him the finger! Sharif says he jumped out of the way... narrowly escaping his fate as Costa Rican roadkill.

But a witness tells TMZ it's all hogwash. He says Mel was trying to enjoy a "sweet pastry" and a cup of coffee, when Sharif walked in the bakery and tried to confront him. He claims Mel asked Sharif to leave, to no avail. The witness says Mel left ... Sharif followed. The witness says at no time did Mel drive toward Sharif. And he says there are at least 7 other witnesses who will tell the same story.