"Caged" complexity classes ? This is a somewhat frivolous question that popped up in my head after reading the various responses to "What's the “smallest” complexity class for which a superlinear circuit bound is known?". 

Answers refer to $\mathsf{S_2 P}$, and when I looked at the zoo entry for it, I discovered this: 


  $\mathsf{S_2-EXP•P^{NP}}$: Don't Ask
  
  One of the caged classes of the
  Complexity Zoo.
  
  Has been implicated in a collapse
  scandal involving $\mathsf{AM}[\text{polylog}]$, $\mathsf{coNP}$,
  and $\mathsf{EH}$


So now I'm intrigued. What's a caged complexity class, and what's the juicy scandal here :) ? The zoo has no references to clarify.
The Complexity Zoo has a reference to that result in the description of the class AM[polylog]:


  […] [SS04] show that if AM[polylog] contains coNP, then EH collapses to S2-EXP•PNP. ([PV04] improved the collapse to AMEXP.) 


In the Complexity Zoo, a class or a statement is caged when it looks very scary.  Examples of caged statements can be found in the descriptions of coNP/poly and SFk (not for the easily scared, reader discretion is advised).