Suggestions for a CR 10 encounter?

[bobthe6th]

Testing a CR 10 monster... anyone got suggestions for a few CR 10 threats to mix in as controls? I have not had any real DM experience, so I don't know what is actually CR 10, and what is to strong/to weak for its CR.

Help a guy out?

[nyjastul69]

What is the party composition? What is the optimization level of the party? What sources are allowed? What is the average ECL of the party?

Edit: Are you looking for CR 10 beasties, or to create an EL 10 encounter? The two are quite different.

[bobthe6th]

I am doing it with a few groups of four, intending to test that my creation is in fact CR 10. I was trying to throw a few of the generaly assumed "balanced" CR 10 encounters at them, then see if my creation was a simaler challenge.

So, any source, but I would like to keep book diving to a minimum, party at flat ECL 10, parties still forming. They seem to be semi optimized, but not to an extreme.

edit: well, the thing I am testing is one CR 10 monster, so I guess stuff that is on par with what that should be...