Tracking Down IP in VMware

I have run into an issue in my environment where an IP was allocated to some device that was already assigned else where.

I knew there was problem when I tried to assign the correct IP to the rebuild VM and it would not connect to the network but change the IP to another one on the same vlans works. When I ping the correct IP it does respond and returns an address the is a VMware address 00:50:56xxxx. I worked with my network team and the helped me narrow this down to one blade. Here is the odd part I have gone through each VM and confirm the MAC assigned to the problem MAC is not listed. I even wrote a powercli script to check my who VMware environment and the MAC is not found yet you can ping the address. I cannot connect to the computer via UNC, Computer Management, SSH etc... but believe it is a windows server since  when I did a telnet to port 80 it is open and see it list Microsoft-HTTPAPI in the banner message.

I already try to run a port scan on the IP and it is useless and did not tell me much. Outside of doing a packet capture on the host any other ideas how I can find this problem server?