The title is a homonym with an old nonsense expression that has nothing to do with rabbits as such.
A man reading a newspaper comes across an article stating that meat prices have soared. Angry, he declares that he'll hunt his own meat to get back at the government for the price inflation. He takes his dog with him, revealing he is going hunting for rabbits.
In the woods, a rabbit leads the dog into a hollow log and pushes the log down a hill, where it smashes into a tree. Meanwhile, the hunter sees several rabbits hopping over a hill. He fires his gun several times and runs to where the rabbits were. When he gets there, he finds two spinning wheels with pictures of rabbits on them, giving the perception of moving rabbits.
The hunter then sees the rabbit sleeping. The hunter starts pouring salt on the rabbit, who quickly gets up and holds a stick of celery under the stream of salt. The rabbit then runs into a cave, and the hunter runs after him. Before he reaches the cave, a pair of elevator doors closes, which the hunter runs into.
The bunny then dresses female dog, successfully seducing the hunter's dog. When the dog finally realizes he's with the rabbit rather than another dog, he resumes his chase. The rabbit then pretends he's a policeman, citing the . He then sings the same song as below. The hunter then finds dog for numerous crimes (speeding, running on the wrong side of the street, intoxiated "driving", etc.).
After confusing the dog and running away, the rabbit begins singing a song about how crazy he is. When he finishes his song, he turns to find the hunter with his gun aimed at him. The rabbit, trying to gain sympathy, begs for his life, explaining how poor and sick he is. The hunter begins crying, feeling sorry for the rabbit. Despite this, the rabbit shocks the hunter with a joy buzzer. The hunter then pronounces that he can whip the rabbit and his whole family. Suddenly, a large group of rabbits surround the hunter, looking for a fight.
The rabbits then attack the hunter leaving him dazed. As the wacky rabbit returns with the hunter's gun. He throws it on the ground and bounces on his head away. The hunter, frustrated, does the exact same thing.
The goofy song the Bugs Bunny "prototype" sings:
All the world was gay.
Swinging on its way.
Things were looking brighter day by day. (laugh)
Nothing ever wrong;
Life was just a song,
'Till that Looney Tune came along. (laugh)
Ohhh. I'm going cuckoo, woo-woo! (laugh)
Here comes the choo-choo, woo-woo! (laugh)
I'm so gooney, looney tuney, te'ched in the head...
Please pass the ketchup,
I think I'll go to bed! Hoo!
Am I the screwball, woo woo! (laugh)
Throw me the 8-ball woo woo! (laugh)
Once I knew a thing or two, but now I'm a buffer*-roo. Hinky dinky parley woo woo!(laugh)
(*): Slang meaning "square" or "mark"
Eight years later, the song would be varied somewhat and reprised by the now fully-realized character Bugs Bunny, in Easter Yeggs:
Here's the Easter Rabbit, hooray! Makin' life funny, hooray! I am gettin' Looney Tuney, touched in the head This whole thing is gooney, I should have stood in bed. Here's the Easter Rabbit, hooray! The happy Easter Rabbit, hooray! Hens would hide the eggs they'd lay, then I give them all away Crazy Easter Rabbit, hooray!
Happy Rabbit has a laugh similar to that of Woody Woodpecker, a character also voiced by Mel Blanc during his first few appearances.
All of Happy Rabbit's family members look identical to each other.
Final cartoon where WARNER BROS. was on a banner.
Porky Pig makes a cameo appearance in a billboard during the Hare-Um Scare-Um song sequence.
Boomerang airs the "dubbed version" without the lost ending since 1995, even after 2012, when the lost ending came out.
The hunter sometimes is known as Egghead's last cartoon before Elmer Fudd, but these characters do not resemble each other other than being hunters.
There has been speculation about the real ending of this cartoon. While the version seen in theaters and television ends abruptly after the rabbits appear following the hunter threatening to beat up the wacky rabbit and his entire family, there were actually two endings that were said to exist.
One ending showed the rabbits attacking the hunter and his dog, followed by an iris-out as the cartoon cloud of hostility rages.
The other ending supposedly showed the rabbits attacking the hunter and his dog and, once the smoke clears, the viewer sees that the hunter and his dog have been reduced to heads and the heads roll off into the sunset.
However, none of these said endings mentioned above were ever true. According to David Gerstein's blog, it shows that the rabbits first attack the hunter in a cartoon smoke and then run away. The smoke clears up to show the hunter disheveled, but head still intact. The rabbit returns to give the hunter his busted rifle saying "You oughtta get that fixed. Somebody's liable to get hurt." He then returns to his looney self, bouncing on his head like a pogo stick down the road. The hunter snaps and goes insane, bouncing on his head like a pogo stick. This scene might have been removed because, as Gerstein theorizes, the ending scene was similar to the ending of Tex Avery's Daffy Duck and Egghead.
Hare-um Scare-um is available with the lost ending restored on Looney Tunes Platinum Collection: Volume 2, Disc 2.