"At approximately 11:15pm last night myself and (girlfriend Lauren Hashian) had to make the painful decision to end Brutus' suffering by taking him off of life support and sending his soul to pup heaven. I held his lil' paw as he was finally at peace … We'll always love you Brutus... and you'll always be my lil' main man and rough housing Brute."
That's because even mushroom experts, called mycologists, have a hard time identifying which are toxic, because such a determination depends on habitat and surrounding plants. They may even harbor more than one poisonous substance.
The rule of thumb, then, is to keep dogs away from all wild mushrooms, just to be safe. Dwayne Johnson used his dog's death to warn other pet parents about the dangers of mushrooms.
"I encourage all of you out there to be mindful of mushrooms in your yards, parks or anywhere outside your dogs play," Dwayne wrote. "What looks innocent, can be deadly to your lil' family members."
Symptoms of toxicity vary depending according to the type ingested. The most dangerous are the kind that destroy the liver and kidneys, like the one Dwayne Johnson's dog ate. Others effect the nervous system or causes gastrointestinal irritation, PetMD explained.
If eaten, a toxic mushroom can cause the following unpleasant symptoms in your pet: vomiting, diarrhea, abdominal pain, weakness, lethargy, jaundice, clumsiness, excessive drooling, seizures, and coma.

So how can you guess which mushrooms are the deadliest? There are actually five particular species that you should watch out for and can be easily identified.
These include the classic toadstool, or "fly agaric," which has a bright red cap, and white spots and stem. It's found in the woods and can cause disorientation. The "jeweled death cap," which is also toadstool-like, but with a yellowish cap instead, and is also found in the woods. Then there's the "death cap," which causes the most fatal poisonings than any other. Delicate and white, only half can kill an adult; it's been known to cause liver failure in animals. "Elf's saddle" has a gray "saddle" and a light stem, and experts don't know too much about it, except that it should be avoided. The lovely-looking, rust-colored "autumn galerina" pop up in yards after a heavy rain. They are nearly always fatal if ingested.
To see photos of these deadly mushrooms, click here.
[Photos Courtesy Mark Metcalfe / Getty Images, Arie v.d. Wolde / Shutterstock]