'Vanderpump Rules' Lala Kent Accuses Tom Sandoval of 'Grooming' Rachel Leviss

Lala Kent accused Tom Sandoval of "grooming" ex-castmate Rachel Leviss amid their months-long affair ... and she went off on him too in dramatic fashion.

The major clash went down during Tuesday's episode of "Vanderpump Rules" ... where Lala and Sandoval butted heads over his handling of cheating on longtime girlfriend Ariana Madix ... not to mention the involvement of Rachel.

As the two reality stars found themselves in an explosive argument -- Sandoval accused Lala of being less forthcoming about her own possible affair with Randall Emmett than he was with his love triangle ... and that set Lala off.

She hit back at Sandoval by calling him "terrifying" and "insane" for pigeonholing her after all these years. Then, surprisingly, Lala came to Rachel's defense and alleged Sandoval had manipulated the former beauty queen.

Apparently, Rachel's comment about needing to "fall in line" with Sandoval at the season 10 reunion left Lala triggered ... who snapped, "You isolate. You groom. You lie.”

She added ... "I do not want to know you. You are scary." Sandoval -- understandably -- rejected the allegation and accused Lala of not really knowing him. It made for good TV.

ICYMI ... 'VPR' made headlines last year after it was revealed that Sandoval had cheated on Ariana, his girlfriend of nine years, with her good friend, Rachel (AKA Raquel).

While the bar owner attempted to apologize as the Scandoval made waves ... he was ostracized by many of his costars for his apparent lack of empathy.

The drama has only grown off-screen ... Rachel hit Sandoval and Ariana with a lawsuit at the end of February -- alleging a number of things, including revenge porn.