He told her that she did not care for the dog, and was going to stab it before stabbing her.
Despite his mother's protests he grabbed a knife from the bench, and as the dog hid under the computer desk McVicar stabbed it once in the neck.
As his mother yelled, he threatened to do ''the same to you'’.
McVicar then threw the knife into the kitchen sink, and returned to watch television.
The dog was described as being highly distressed and was bleeding profusely, requiring treatment.
McVicar admitted the offending, telling police he wasn’t in a good state of mind.