The bilingual Exeggutor is a Japanese promo card, number 103, that carries both English and Japanese text on its front. It exists in two 1999 printings that look almost identical, plus a modern reprint. The first was handed to players at the 1999 Tropical Mega Battle in Hawaii, and fewer than 50 of those were given out. The second was a reprint distributed later the same year in the Official Pokemon Trainers Magazine, Volume 3, and far more of those were made. Telling the two apart comes down to the card stock and to a caricature in the corner of the artwork.
What was the Tropical Mega Battle?
The Tropical Mega Battle was an invitational tournament held at the Hilton Hawaiian Village from 24 to 27 August 1999. It is widely treated as the first Pokemon world championship, though it was not branded that way at the time.
Players reached it by two main routes. The top 12 DCI-ranked American players, aged 11 to 14, received automatic invitations. Japanese players qualified through nine regional events run over the summer of 1999, with the first, second and third place finishers at each event earning an invite. Players from Canada, Latin America and Asia also attended.
Every attendee received the bilingual Exeggutor at the closing ceremony. It was a participation card rather than a prize for winning, which is why the print run tracks attendance rather than placement.
Why is the card bilingual?
The event put Japanese and English-speaking players in the same room, so the card was printed with both languages on the front. That is unusual for a Pokemon card and it is the reason collectors named it the way they did. Most promos of the era targeted one market and printed one language.

How many were made?
Fewer than 50 were distributed at the event. Beyond that the number is genuinely uncertain. Attendance estimates run from 36 to 50, and collectors who have worked the problem tend to settle around 36 to 42, partly by comparing against the following year's event, which recorded 42 players representing nine countries.
Treat any precise figure with suspicion. No official attendance list has surfaced, an unknown number of cards were lost or damaged over the following decades, and the population that survives in collectable condition is smaller again.
The Trainer Magazine reprint is a different story. It went out to magazine subscribers later in 1999, and while no exact print figure is published, it is the version you are far more likely to encounter.
How do you tell the two versions apart?
Three things separate them, and it helps to check more than one.
Finish. The Tropical Mega Battle card is matte. The Trainer Magazine reprint is glossy. This is the fastest check if you can see the card under a light, and it is the difference most collectors reach for first.
Colour. The tournament card looks washed out, with noticeably less saturation. The magazine version is richer and the black text reads bolder. On the tournament card the text has a fainter, almost pencil-like quality, and some copies look slightly blurry.
The Ooyama caricature. The artwork was drawn by Kouichi Ooyama, who put a caricature of himself in the bottom right corner of his own illustration. On the tournament version his tie runs slightly longer. On the magazine reprint it has a cut-off look where the tie is cropped at the bottom of the image.
Do not try to separate them by the credit line along the bottom of the card. The scan Bulbagarden catalogues as the tournament promo carries a line naming Trainers Vol. 3, which means either that both printings share the same credit text or that the catalogued scan is of the magazine version. Neither possibility leaves the bottom line usable as a test.
This is the more direct check of the three, and it is the one to use when you cannot judge the card stock. Finish and colour are both hard to read from a listing photo, and a seller's lighting can flatter either version. The tie either matches or it does not.
Why is the tournament version so expensive?
Two facts do all the work. The non-glossy card went only to people who were in the room in Hawaii in August 1999, and there were fewer than 50 of them. The glossy card went out through a magazine to anyone who subscribed.
The awkward part is that the two look nearly identical. A card whose scarcity differs by orders of magnitude from its twin, where the difference is a surface finish and the length of a cartoon tie, is exactly the kind of card where buyers overpay for the common version and sellers occasionally undersell the rare one. That is the whole reason the identification detail is worth learning before you shop.
Is there a modern reprint?
Yes. The artwork returned in 2016 as Exeggutor 109/108 in XY Evolutions, a secret rare released on 2 November that year. It is an 80 HP Grass Pokemon and the illustrator credit still reads Dr. Ooyama.
Evolutions rebuilt Base Set in a modern frame, so this printing pairs the original artwork with a template styled after the original series. There is no risk of confusing it with either 1999 card. It is a modern English card with a modern back and a set symbol, and it sits in a set that anyone can still buy sealed.
It does mean the artwork itself is cheap to own. If what you like is the Ooyama illustration rather than the event provenance, the Evolutions secret rare is the accessible way to get it, and it is a real chase card in its own set rather than a filler reprint.

Which version should you buy?
That depends on what you are collecting. The magazine reprint is an affordable way to own the design and it is a legitimate 1999 card in its own right. The tournament card is a piece of competitive Pokemon history from the event that preceded the World Championships, and it is priced accordingly.
If you are paying tournament-card money, the finish, the colour and the tie should all agree with each other before you commit. A graded copy resolves the question, and it is worth noting that the two printings are catalogued separately, so the label will tell you which one you are looking at.
Sources
The distinguishing details here come from two Elite Fourum threads, The 1999 Tropical Mega Battle Bilingual Exeggutor and Distinguishing Trainer Magazine and Tropical Mega Battle Bilingual Exeggutor, with event and card details cross-checked against Bulbapedia. The Evolutions reprint details come from PkmnCards.