Per 
Item#: SCP-XXXX
Object Class: Euclid
Special Containment Procedures: SCP-XXXX is to be contained in a 50 in x 50 in x 50 in steel vault that must require a key card Level 3 or higher to open. The vault must have a minimum of ONE combination lock and ONE key card-activated lock. If it IS to be handled outside of the containment chamber, proper equipment such as gas masks must be worn in the case of any gas leaks.
Description: SCP-XXXX appears to be an ordinary canister of laughing gas. It is painted a pine-green colour and has a large retro 90's sticker that depicts a rainbow in the sky with large bold text reading "SMILE!".
SCP-XXXX was found in an abandoned '90s military base and has proven to sicken those who breathe it in. First and foremost, any testing that is done on SCP-XXXX MUST be used only with Class C or D personnel. Infected victims must be kept away from others in order to avoid any ██████. This illness has been proved to be curable and has three recognisable and observable phases of symptoms. It can only be cured or treated whilst in the first two phases. SCP-500 appears to be the most effective treatment so far. A psychiatrist or other mental health professional is REQUIRED to be administered to victims if they do survive.
Infected personnel have reported seeing the canister materialise into a tall, lanky shadow which brings upon feelings of pure dread. According to these victims, the shadow is male and has no face. On rare occasions, he has been said to have a large, happy, smiling expression that consists of nothing but his mouth. He does not interact with the test subjects. He stays around them silently but begins to laugh once Phase II begins.
This 'laughing man', as he is commonly referred to, has a simple goal. To drive someone mad whilst also mirroring their mental state with awful physical effects. All of this, while they are smiling.
"He says he wants to bring joy." One deceased test subject, ███ ██, told the officially-required psychiatrist.
Phase I symptoms include things such as nausea, vomiting, and uncontrollable fits of laughter.
Phase II symptoms include things such as blurred vision, mild hearing loss, and loss of balance.
Phase III symptoms include things such as tumours, loss of depth perception, and internal bleeding.
These people have died from either the fatal phase III effects or from suicide. Some have not been able to recover with a professional's help which leads them to end their lives.
