How to manually run application as "IIS APPPOOL\MyAppPool" user

I tried:

runas /noprofile /user:"IIS APPPOOL\MyAppPool" cmd.exe

But it asks me for a password. My admin password does not work there.

I get:

RUNAS ERROR: Unable to acquire user password


You can't do that. IIS AppPool\<user> accounts are "Application Pool Identity" accounts which are synthesised by IIS when the pool is running. ApplicationPoolIdentity account lifetimes are managed entirely by IIS and the OS and you'll never be able to authenticate interactively with them.