She gave Beowulf Grendels claw.
Beowulf is extremely confident of his victory over Grendel. That was a victory he was proud of, he kept Grendels arm as a trophy basically. He wanted to show off that HE was the one to defeat the moster Grendel and that no one else did. So once Grendels mother took the arm away from him she took his "trophy" away from him. By Grendels mother taking the arm she was basically testing Beowulf. She was basically trying to show that she took his "trophy" back and if he wanted it back he had to go to her lair and get it himself.
A swamp
1
he dies later on
Underwater, in a lake.
you mean hangs grendels hand if so than because to show that he can kill Grendel you mean hangs grendels hand if so than because to show that he can kill Grendel
God's Power
To steal back Grendels arm
the word spread by worriers who escaped.
The Sword breaks
Under water, where Grendel's mother lived.