The Canadian-English noun Bloody Caesar designates a drink consisting of vodka and Clamato juice.

This noun was coined after Bloody Mary, which designates a cocktail consisting of vodka and tomato juice.
—Cf. also:
– the Bloody Mary before the name existed;
– Who invented—and named—the Bloody Mary?.

The Bloody Caesar is said to have been invented in 1969 by Walter Chell (1926-1997), a bartender at the Calgary Inn (subsequently the Westin Hotel), in Calgary, Alberta, Canada, to accompany the opening of a new Italian restaurant on the premises.

Tom Moore, Albertan staff writer, mentioned an “Italian concoction” called Bloody Caesar when writing about the opening of this new Italian restaurant in Ever think of eating Italian-style?, published in The Albertan (Calgary, Alberta, Canada) of Thursday 30^th October 1969:

GOOD MORNING to everyone—and especially to Calgarians who plan to take a course in gourmet eating and wine-bibbing, Italian style, at today-debuting Marco’s were [sic] they’ll prove to you that there’s more to Italian dining than pizza, spaghetti and chianti.
To keep from scaring you away, let it be stated here and now that this is not a paid commercial. In fact, the boys and girls at Marco’s might like to pay to keep you from reading it.
For one thing, the place has already gone downhill.
To get into it a few days ago, when members of the press got a preview, the entrance was a very interesting route through an unfinished basement area, into a boiler room, up a back staircase, under a ladder and painters’ scaffold and through assorted debris-strewn corridors. At today’s public opening, you’ll just walk through a door.
They’ll also try to kid you that everything is genuine and traditional Italian.
It isn’t. The beautiful Venetian glamor girls who masquerade as waitresses all speak English. So do the Sicilian brigands who have [been] hired out as waiters. And when you order Mezzo Pollo Giovano Alla Diavalo [sic] in your best Italian, don’t be surprised when they bring you Half Broiled Spring Chicken a la Diable with Wine and Mustard like it says in the small type on the menu. English, yet.
And even though thhe [sic] wine list offers such Italian concoctions as “Casanova’s Delight”, “Romeo”, “Bloody Caesar”, “Lucrezia” and “Roman Flirt”, (and a fancy-bottled vintage called Bertolli Vinrosa that comes in [a] spectacular spouted, basket-wound, ice-compartmented bottle that is sure to become a local status symbol) who ever heard of a Neapolitan bistro selling Alberta beer, a Moscow mule, Planters’ Punch and a Zombie?
As an added feature of the press-opening, the Calgary Inn’s executive chef, Wolfgang Goudrian, took on two local radio types in a spaghetti eating contest. It was won by that old Italian epicure, Howardo L’Angdello, with Luigi Belli second.
[…]
Incidentally, if you are interested in some of the behind-the-scenes technical stuff about Marco’s, you may like to know […] that at an early date there will be a skywalk from the Calgary Inn, across the street, to Marco’s . . . ostensibly to make access easier than the parking lot-boiler room-back stairway route used by the press but really to make the place more accessible for L. Marc Hamel, the Inn’s general manager, who has his eye on those special Bertolli Vinrosa bottles.

The following, from The Calgary Herald (Calgary, Alberta, Canada) of Friday 4^th February 1972, mentions that Walter Chell claimed to have invented the Bloody Caesar:

But he’s glad to make you a Bloody Caesar
Bartender prefers Scotch

By Alan Mettrick
(Herald Staff Writer)
[…]
[…] Right now it’s Bloody Caesar that occupies the mind of Walter Chell, barman extraordinary.
Behind the dark bar of the Calgary Inn he pours vodka over ice and adds a quarter of fresh lime and his own concoction of spices. Then he pours on four ounces of clam nectar and tomato juice (Clamate) and adds a celery stick and serves.
One Bloody Caesar. A dream machine for $1.80.
The whole exercise takes maybe half a minute and Walter conducts it with a proprietary air. He should because he invented the drink. It is HIS drink.
But Walter is miffed and he is not hiding it. The fact is that others have of late been claiming the Bloody Caesar as their own.
The reaction of Walter Chell, world-renowned beverage expert, is akin to that of Leonardo da Vinci faced by some upstart house painter claiming credit for the Mona Lisa.
“I work three whole days to make. Now you can buy all over place Bloody Caesar and everybody tell you it is THEIR drink.”
Walter, beverage manager of the Calgary Inn, is incensed by this banditry but his voice is raised barely above a whisper because he abhors loudness in his bar.
He is upset not because others are using their version of his drink. That is a compliment. But the fact that in other bars other people are claiming they originated the drink angers him.
He is so upset that he has resorted to the unusual step of putting out a press release, staking his claim to the drink which is sold at his bar in hundreds every day.

However, in the following letter to the Editor, published in The Calgary Herald (Calgary, Alberta, Canada) of Thursday 10^th February 1972, Judith E. Hughes, of Calgary, claimed that the drink existed before the noun Bloody Caesar itself first appeared:

I must take issue with your reporter Alan Mettrick on a slightly less-than-vital issue concerning bartender Walter Chell and “his” Bloody Caesar. On a trip to California six years ago my husband and I were introduced to the rage drink of the time—vodka, “Mott’s clamato juice,” lime juice and tabasco sauce. On returning to Vancouver we were delighted to find the stores were stocking the clam nectar and tomato juice mixture.
Since 1966 we have enjoyed this delightful mixed drink every summer, routinely.
Mott Company of the U.S.A. has advertised this drink since the introduction of their product.
The only thing Walter Chell could be credited with is the peculiar name he had dubbed our favorite drink with—“Bloody Caesar.”