Frustrated that his house is constantly being burglarized, a man visits a pet store to find a guard dog. The store owner proudly brings out a huge 175-pound German Sheperd named T-Rex.
"He's a big dog, but he looks kinda tame," the customer notes.
"Watch this," the store owner replies. "T-Rex! Where's the burglar?! Where's the bad guy?!"
Immediately, the dog becomes a raving, vicious beast, it's barking like the the booming of a cannon, it's sharp teeth bared and snapping. The store owner even feeds the dog a metal pipe which it bites in half!
"It's safe, T-Rex! Good boy!" the store owner assures the dog, which calms down instantly, given the secret password.
"Wow! That's some dog! That's exactly what I need! But, how much does he cost?" the customer asks, expecting a hefty price.
"T-Rex can be yours for just $100."
The customer can't believe his luck, and gladly pays for T-Rex.
That night, the customer is awoken by breaking glass and voices downstairs! His house is being broken into again! He waits in vain for his new dog to bark and attack the crooks, but nothing happens.
When the burglars leave, the customer goes downstairs to find his valuables gone, T-Rex sleeping peacefully on the floor.
Angry, the customer brings the German Sheperd back to the pet store the next day and complains that T-Rex was completely useless, actually sleeping through the vandalsm.
The store owner pulls a little Shih Zhu out of a cage and says, "For another $900 you can have this little dog to wake him up!"