I've been trying to convince CB Drafters for the last year that Randolph is a savant. Now, maybe they'll believe me.

Seriously, though, the way the guy is playing right now, there isn't a player in the league who could stop him. He'd be getting points on a Rodman / Dikembe duo right now. He's hitting runners, fadeaways, threes, rainbows, and just about any other shot he takes. It's amazing.
I think he took the shot at Perk just to trash talk a bit. I don't think "you can't guard me, nobody can guard me" is the most objective of observations, but it's probably true at this point.
Lastly, it's important to remember that Perk is a center, rather than a power forward. If anybody should be talking trash, it's Gasol; Randolph should be Ibaka's responsibility.