diff --git a/spec/spectator/mocks/lazy_double_spec.cr b/spec/spectator/mocks/lazy_double_spec.cr
index ef060a3..1f60224 100644
--- a/spec/spectator/mocks/lazy_double_spec.cr
+++ b/spec/spectator/mocks/lazy_double_spec.cr
@@ -59,56 +59,54 @@ Spectator.describe Spectator::LazyDouble do
   end
 
   context "with common object methods" do
+    let(dup) { double(:dup) }
+
     subject(dbl) do
       Spectator::LazyDouble.new(nil, [
-        Spectator::ValueStub.new(:"!=", "!="),
-        Spectator::ValueStub.new(:"!~", "!~"),
-        Spectator::ValueStub.new(:"==", "=="),
-        Spectator::ValueStub.new(:"===", "==="),
-        Spectator::ValueStub.new(:"=~", "=~"),
-        Spectator::ValueStub.new(:class, "class"),
-        Spectator::ValueStub.new(:dup, "dup"),
-        Spectator::ValueStub.new(:hash, "hash"),
+        Spectator::ValueStub.new(:"!=", false),
+        Spectator::ValueStub.new(:"!~", false),
+        Spectator::ValueStub.new(:"==", true),
+        Spectator::ValueStub.new(:"===", true),
+        Spectator::ValueStub.new(:"=~", nil),
+        Spectator::ValueStub.new(:dup, dup),
+        Spectator::ValueStub.new(:hash, 42_u64),
         Spectator::ValueStub.new(:"in?", true),
         Spectator::ValueStub.new(:inspect, "inspect"),
-        Spectator::ValueStub.new(:itself, "itself"),
-        Spectator::ValueStub.new(:"not_nil!", "not_nil!"),
+        Spectator::ValueStub.new(:itself, dup),
+        Spectator::ValueStub.new(:"not_nil!", dup),
         Spectator::ValueStub.new(:pretty_inspect, "pretty_inspect"),
-        Spectator::ValueStub.new(:tap, "tap"),
+        Spectator::ValueStub.new(:tap, dup),
         Spectator::ValueStub.new(:to_json, "to_json"),
         Spectator::ValueStub.new(:to_pretty_json, "to_pretty_json"),
         Spectator::ValueStub.new(:to_s, "to_s"),
         Spectator::ValueStub.new(:to_yaml, "to_yaml"),
-        Spectator::ValueStub.new(:try, "try"),
+        Spectator::ValueStub.new(:try, nil),
         Spectator::ValueStub.new(:object_id, 42_u64),
         Spectator::ValueStub.new(:"same?", true),
       ] of Spectator::Stub)
     end
 
     it "responds with defined messages" do
-      hasher = Crystal::Hasher.new
       aggregate_failures do
-        expect(dbl.!=(42)).to eq("!=")
-        expect(dbl.!~(42)).to eq("!~")
-        expect(dbl.==(42)).to eq("==")
-        expect(dbl.===(42)).to eq("===")
-        expect(dbl.=~(42)).to eq("=~")
-        expect(dbl.class).to eq("class")
-        expect(dbl.dup).to eq("dup")
-        expect(dbl.hash(hasher)).to eq("hash")
-        expect(dbl.hash).to eq("hash")
+        expect(dbl.!=(42)).to eq(false)
+        expect(dbl.!~(42)).to eq(false)
+        expect(dbl.==(42)).to eq(true)
+        expect(dbl.===(42)).to eq(true)
+        expect(dbl.=~(42)).to be_nil
+        expect(dbl.dup).to be(dup)
+        expect(dbl.hash).to eq(42_u64)
         expect(dbl.in?([42])).to eq(true)
         expect(dbl.in?(1, 2, 3)).to eq(true)
         expect(dbl.inspect).to eq("inspect")
-        expect(dbl.itself).to eq("itself")
-        expect(dbl.not_nil!).to eq("not_nil!")
+        expect(dbl.itself).to be(dup)
+        expect(dbl.not_nil!).to be(dup)
         expect(dbl.pretty_inspect).to eq("pretty_inspect")
-        expect(dbl.tap { nil }).to eq("tap")
+        expect(dbl.tap { nil }).to be(dup)
         expect(dbl.to_json).to eq("to_json")
         expect(dbl.to_pretty_json).to eq("to_pretty_json")
         expect(dbl.to_s).to eq("to_s")
         expect(dbl.to_yaml).to eq("to_yaml")
-        expect(dbl.try { nil }).to eq("try")
+        expect(dbl.try { nil }).to be_nil
         expect(dbl.object_id).to eq(42_u64)
         expect(dbl.same?(dbl)).to eq(true)
         expect(dbl.same?(nil)).to eq(true)
@@ -123,47 +121,28 @@ Spectator.describe Spectator::LazyDouble do
   context "without common object methods" do
     subject(dbl) { Spectator::LazyDouble.new }
 
-    it "raises with undefined messages" do
+    it "returns the original value" do
       io = IO::Memory.new
       pp = PrettyPrint.new(io)
       hasher = Crystal::Hasher.new
       aggregate_failures do
-        expect { dbl.!=(42) }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.!~(42) }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.==(42) }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.===(42) }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.=~(42) }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.class }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.dup }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.hash(hasher) }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.hash }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.in?([42]) }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.in?(1, 2, 3) }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.inspect }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.itself }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.not_nil! }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.pretty_inspect }.to raise_error(Spectator::UnexpectedMessage)
-        # expect { dbl.pretty_inspect(io) }.to raise_error(Spectator::UnexpectedMessage)
-        # expect { dbl.pretty_print(pp) }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.tap { nil } }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.to_json }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.to_json(io) }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.to_pretty_json }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.to_pretty_json(io) }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.to_s }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.to_s(io) }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.to_yaml }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.to_yaml(io) }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.try { nil } }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.object_id }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.same?(dbl) }.to raise_error(Spectator::UnexpectedMessage)
-        expect { dbl.same?(nil) }.to raise_error(Spectator::UnexpectedMessage)
+        expect(dbl.!=(42)).to be_true
+        expect(dbl.!~(42)).to be_true
+        expect(dbl.==(42)).to be_false
+        expect(dbl.===(42)).to be_false
+        expect(dbl.=~(42)).to be_nil
+        expect(dbl.class).to be_lt(Spectator::LazyDouble)
+        expect(dbl.in?([42])).to be_false
+        expect(dbl.in?(1, 2, 3)).to be_false
+        expect(dbl.itself).to be(dbl)
+        expect(dbl.not_nil!).to be(dbl)
+        expect(dbl.tap { nil }).to be(dbl)
+        expect(dbl.to_s(io)).to be_nil
+        expect(dbl.try { nil }).to be_nil
+        expect(dbl.same?(dbl)).to be_true
+        expect(dbl.same?(nil)).to be_false
       end
     end
-
-    it "reports arguments" do
-      expect { dbl.same?(123) }.to raise_error(Spectator::UnexpectedMessage, /\(123\)/)
-    end
   end
 
   context "with arguments constraints" do
@@ -201,6 +180,14 @@ Spectator.describe Spectator::LazyDouble do
       it "raises an error when argument count doesn't match" do
         expect { dbl.same? }.to raise_error(Spectator::UnexpectedMessage)
       end
+
+      context "with a fallback defined" do
+        subject(dbl) { Spectator::LazyDouble.new(nil, [stub], "same?": true) }
+
+        it "returns the fallback when constraint unsatisfied" do
+          expect(dbl.same?("baz")).to be_true
+        end
+      end
     end
   end
 
diff --git a/src/spectator/mocks/lazy_double.cr b/src/spectator/mocks/lazy_double.cr
index 36582bb..accaa46 100644
--- a/src/spectator/mocks/lazy_double.cr
+++ b/src/spectator/mocks/lazy_double.cr
@@ -3,6 +3,7 @@ require "./arguments"
 require "./double"
 require "./method_call"
 require "./stub"
+require "./value_stub"
 
 module Spectator
   # Stands in for an object for testing that a SUT calls expected methods.
@@ -17,8 +18,12 @@ module Spectator
     @name : String?
 
     def initialize(_spectator_double_name = nil, _spectator_double_stubs = [] of Stub, **@messages : **Messages)
-      super(_spectator_double_stubs)
       @name = _spectator_double_name.try &.inspect
+      message_stubs = messages.map do |method, value|
+        ValueStub.new(method, value)
+      end
+
+      super(_spectator_double_stubs + message_stubs)
     end
 
     # Returns the double's name formatted for user output.