Prinz von Anhalt's Son Kevin Feucht Shocked About Adoption Reversal

Prince Frédéric Prinz von Anhalt's recently-adopted son, Kevin Feucht, can't believe his dad wants to un-adopt him .. and says he won't go quietly, in fact, he's looking punish him.

We got Kevin outside Wally's Monday in Bev Hills and he told us he's "shocked, disappointed, and sad" Prinz wants to reverse the adoption process. While Zsa Zsa Gabor's widower has claimed his son isn't spending time with him, Kevin says, "I've put so much effort and time into this."

Kevin tells TMZ he wants to "slightly punish" his dad, although he wasn't specific about exactly how he'd do that. Not shockingly, we think, he says Prinz has been ignoring him since last week.

You'll recall ... Anhalt says he adopted Kevin to carry on his and Zsa Zsa's royal lineage.

But, if we're keeping it real -- the adoption was featured on the reality show, "Adults Adopting Adults." When A&E canceled it after 3 episodes ... Prinz decided to reverse the adoption process.

Kevin says he really wants things to work out, knowing how big of a legacy Zsa Zsa left behind, and it sounds like he already had big plans.