NICOLAS CAGE is suing a former business manager for $20 million . . . claiming the guy mismanaged his money and nearly put him in the poorhouse.

--But it sounds like Cage played a part in his financial ruin, too . . . by being an out-of-control spender.  Check out some of the things Cage bought over the years . . . many of which he's had to SELL OFF just to stay in the red . . .

--At least two yachts and a Gulfstream jet.

--Dozens of cars and motorcycles . . . including a $500,000 Lamborghini that had been confiscated from the Shah of Iran.

--A real dinosaur skull that he bought for $276,000 . . . after outbidding LEONARDO DICAPRIO for it.

--Two private islands in the Bahamas and two CASTLES . . . one in England and one in Germany.

--And how about this:  Two KING COBRAS . . . named Moby and Sheba.  He also had the antidote for their venom on the wall . . . you know, just in case.

(--That's like owning a pit bull.  It's not really bad-ass.  Just kind of stupid.  Doesn't Nic remember what a King Cobra did to the Macho Man Randy Savage on "WWF Superstars" almost 20 years ago???)

(--If you've never seen that classic moment, you simply MUST check it out . . .)

http://www.ebaumsworld.com/video/watch/822887/