be something else

1. To be hilarious and extremely entertaining. A: "So then I said, 'That's not a lady—that's my wife!'" B: "Hahaha, oh Jack, you are something else." Jack's story was something else, wasn't it? I thought I was going to cry, I was laughing so hard!

2. To be very remarkable or intriguing. That performance was something else, Sarah. I've never seen anything like it! You're something else, Mark. I'm just constantly in awe of what you are able to achieve in this company.

3. To be abhorrent or repugnant. I mean, we've all done things we're not proud of. But stealing money from your dying mother? That's something else, Marty.

something else, he/she/it is

Someone or something is extraordinary, in a positive sense. It does not mean “something different” but is a slangy elaboration of the simpler “isn’t that something.” It is usually said admiringly, as in “Kayla Cole is something else” (James Patterson, London Bridges, 2004).