Tristan Thompson appears to have beef with Lamar Odom ... and Khloe Kardashian is smack in the middle of things.
Here's the deal ... Khloe posted an Instagram photo Friday showing her taking an outdoor shower in a skimpy bikini, and Lamar complimented her in the comments, telling her she's a "hottie" ... a response Tristan's not taking kindly.
Tristan tagged Lamar in the comments and then seemed to loft a threat his way, writing ... "@lamarodom God brought you back the first time. Play if you want, different results 🤷🏽♂️🤷🏽♂️"
The comment is obviously referring to Lamar's infamous 2015 drug overdose at a Nevada brothel, which nearly killed the former NBA stud.
As you know ... Tristan's got a child with Khloe, but she's got a long history with Lamar. Khloe and Odom were married from 2009 to 2016 and they had their own reality show, "Khloe & Lamar."
Tristan and Khloe recently called it quits (again) after allegations of cheating (again) ... but he wished her happy birthday last month on his IG and often comments on her posts.
Seems Tristan wants to be Khloe's only ex in her IG comments.