Lol that's what my mom's dog is like. My dog tries to jump on the bars and occasionally misses whacks her head and whines like she's been mortally wounded.
The perspective of this shot makes the spiders look larger than they really are. Generally grow up to 8 inches on average.
They don't scream or numb their victims as urban myth suggests, the biggest risk to someone bitten by one is the size of the wound due to the risk of infection.