Ricin is an organic poison that can be made from castor beans: yes folks, those beans really are trying to kill you and ricin is a great proof that not everything "natural" is actually good for you.

Ricin is poisonous if inhaled, injected, or ingested, acting as a toxin by the inhibition of protein synthesis. Ricin is 6000 times more toxic than cyanide and 12000 times more poisonous than rattlesnake venom by weight. While there is no known antidote, the US military has developed a vaccine.[2] Symptomatic and supportive treatment is available. Long term organ damage is likely in survivors. Ricin causes severe diarrhea and victims can die of shock.

The reason this information about ricin is so important is that there was a plot (not a very good one, admittedly) in the UK to use ricin in a terrorist attack. And some ricin has just been found in a Las Vegas hotel, so was this ricin intended to be used in a terror attack?

Preliminary tests indicate that a package found at a
motel contained the toxin ricin, and seven people have been taken to
hospitals, authorities said.

Police were called to the Extended Stay America Motel
on Thursday and retrieved a package from the motel manager that was
determined to be a chemical or controlled substance, Officer Ramone
Denby said.

Two preliminary tests indicate it contained ricin, he
said. Results from further tests by the Centers for Disease Control and
Prevention and a second local lab are expected Friday, police said.

"Ricin has no medical uses other than cancer
research," police Captain Joseph Lombardo said at a news conference
Thursday night. "An individual citizen other than being involved in
cancer research or cancer prevention would not have any legal means or
proper means of having that."

The authorities are not treating the finding of ricin sa being part of a terror attack:

Ricin, a deadly poison, was discovered in a hotel room in Las Vegas but
officials don’t believe the incident is terrorism-related, media
reported on Friday.

Umm, no, it’s not a gas:

It is being reported that a mysterious package containing the poison gas called ricin has been found in a Los Vegas motel, resulting in 7 people being taken to hospital.
That’s better, ricin is usually a powder:
Ricin, a substance used for cancer research that has "no other medical use," was discovered about 3 p.m. by a man who was cleaning out a suite at the Extended Stay America at 4270 S. Valley View Blvd., Joseph Lombardo, a Las Vegas police captain and Homeland Security Bureau chief, said at a news conference about 9:30 p.m.
The man, who told police the toxic agent did not belong to him, took the powdery substance to the manager’s office, and the manager called police.

How the ricin news was reported: