I haven't come across much information about this tank other than what could be gathered from the picture and a documentary on German armour that was filmed in part at Aberdeen Proving Grounds, Maryland, where this vehicle is on display. Without quoting, the purpose of this was explained as follows;

German engineers would dig a hole.
They would then line the hole with concrete.
The Grasshopper would arrive at some time at the hole.
At this time the turret would be removed from the hull where it
would be placed in the hole that the engineers prepared to receive it.

Note in the picture above some of the equipment resting on the track guard used in performing this job.

This sounds like an interesting way to make a pillbox however, the narrator criticized the concept on the grounds of taking a sound "mobile" weapon, removing its gun to put it in the ground in a fixed position. A process that could be repeated numerous times. I agree with the criticism, any gun could have been used of this caliber in a prepared pillbox leaving the panzer intact to be used as it was intended to be; as a mobile weapon. Maybe this was realized quickly leaving just a few of these tanks being built. The number ranges as low as 3 and as high as 10 tanks converted.

How many turrets were placed in the ground and where, I haven't heard any number or location.
Why was it named "Grasshopper"? Your guess may be better than mine.

This panzer was designed on the versatile and proven Pz Kpfw IV chassis.
The turret was capable of rotation after being placed in the ground.
The gun was a 10.5 cm Howitzer.
It was introduced in 1943.

German prisoners who were lucky enough to end up in America enjoyed many luxuries. A typical recreation room at POW camps came complete with several ping-pong tables, a dozen chess boards, packs of cards, bingo sets, and a phonograph. At Camp Campbell Kentucky they had an incredible collection of 50 records ranging from "Home on the Range," "Missouri Waltz." "Can't Get Indiana Off My Mind," to name just a few. But the most popular record at Camp Campbell and most other camps was Bing Crosby's “Don't Fence Me In!”