A usually solid Kansas State basketball player had a TERRIBLE second half Monday night ... blowing THREE point-blank dunks -- in just 12 game minutes!

The guy's name is Makol Mawien ... and he's actually been a pretty good player for the Wildcats -- starting all 26 games for the team this season.

But, against West Virginia ... he was pretty much the anti-Shaq --- clanking not one, but THREE dunks off iron!!!

The first came at the start of the second half ... Mawien missed a left-handed slam that ended up in the first row of the stands.

The second and third came minutes later -- and just seconds apart from each other -- when Mawien rattled TWO balls off the rim with no defenders even CLOSE to him.

You could tell Mawien was embarrassed ... dude tapped his chest and slapped hands with all his teammates.

After the third miss, KSU coach Bruce Weber didn't even get mad -- putting his arms around Makol to try and help the guy get his confidence back.