I don't know that these have catchy names. In perlref this is referred to as dereferencing a BLOCK that returns a reference. But I don't think I've ever heard anyone refer to these as such. From perlref:

2.  Anywhere you'd put an identifier (or chain of identifiers) as part
+ of a
   variable or subroutine name, you can replace the identifier with a 
+BLOCK
   returning a reference of the correct type.  In other words, the pre
+vious
   examples could be written like this:

       $bar = ${$scalarref};
       push(@{$arrayref}, $filename);
       ${$arrayref}[0] = "January";
       ${$hashref}{"KEY"} = "VALUE";
       &{$coderef}(1,2,3);
       $globref->print("output\n");  # iff IO::Handle is loaded

   Admittedly, it's a little silly to use the curlies in this case, bu
+t the
   BLOCK can contain any arbitrary expression, in particular, subscrip
+ted
   expressions:

       &{ $dispatch{$index} }(1,2,3);      # call correct routine

   Because of being able to omit the curlies for the simple case of "$
+$x",
   people often make the mistake of viewing the dereferencing symbols 
+as
   proper operators, and wonder about their precedence.  If they were,
   though, you could use parentheses instead of braces.  That's not th
+e
   case.  Consider the difference below; case 0 is a short-hand versio
+n of
   case 1, not case 2:

       $$hashref{"KEY"}   = "VALUE";       # CASE 0
       ${$hashref}{"KEY"} = "VALUE";       # CASE 1
       ${$hashref{"KEY"}} = "VALUE";       # CASE 2
       ${$hashref->{"KEY"}} = "VALUE";     # CASE 3

   Case 2 is also deceptive in that you're accessing a variable called
   %hashref, not dereferencing through $hashref to the hash it's presu
+mably
   referencing.  That would be case 3.
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