A Taco Bell manager poured scalding water on two customers who complained that the restaurant got their order wrong, sending them to the hospital with serious burns, this according to a recently filed lawsuit.

In their $1 million suit, Plaintiffs Brittany Davis and her niece, a minor identified only as C.T., claim they pulled up to a drive-thru at a Taco Bell in Dallas and placed a $31 order, but they didn't get what they wanted.

So they circled through the drive-thru 2 more times to rectify the situation, but the employee was having none of it.

The pair then allegedly parked their vehicle and tried to walk inside the fast-food joint, but it was already closed. An employee unlocked the door, allowing them to enter.

After the two asked for their order to be corrected, one of the workers allegedly challenged C.T. to a fight before the manager appeared, holding a bucket of piping hot water.

The manager then doused C.T.'s face with the boiling water, which splashed the chests of both plaintiffs, according to the suit filed July 13 by prominent civil rights attorney Ben Crump.

Luckily, the two were able to escape before they could be attacked again by Taco Bell staff, who laughed and clapped as they drove away, the suit claims.

Davis says she suffered deep burns to her chest and stomach along with brain injuries, which have caused at least 10 seizures. C.T. says she sustained discoloring and scarring burns to her face, chest, legs, arms and stomach.

Dallas PD is investigating the incident, which occurred on June 17.

Crump tells TMZ ... "Not only did Brittany and C.T. Suffer physical trauma because of the burns but they will now live with the psychological trauma that comes with an attack like this. Corporations have a duty to employ quality and stable employees who hold safety as the highest priority.”

We reached out to Taco Bell ... so far no word back.