Origin

The origin of "Spy sappin mah sentry" comes from the video game 'Team Fortress 2'. In this team-based FPS game created by Valve, there are 9 different 'classes' to choose before and during a match. One of them is called the 'Spy'.

The Spy is armed with different kind of weapons, suiting his character. The weapon which is relevent to this meme is called the 'Electro Sapper' or 'Sapper'. However this 'weapon' doesn't affect any character from the opposing team, it is used to disable, draining energy and eventually destroying any building which is constructed by the 'Engineer'-class from the opposing team. These buildings are 'Sentry guns'/'Sentries' (automated turrets), 'Dispensers' and 'Teleporters' (entrances and exits) to help your teammates quicker to the frontline. If a Spy from the enemy team uses his 'sapper' to disable the Engineer's Sentry gun, then the Engineer will automatically respond with: "Spy's sappin' my/mah sentry".

Where this meme started is a bit difficult to pinpoint but due to the catchiness of this phrase, a lot of image parody's were created on the popular video game captioning website Halolz and other forum websites, which made it pretty popular. The one thing we know is that it wasn't spread on Youtube. The existing videos of "Spy sappin' mah sentry" don't have that much attention. So it is possible that it was mostly spread on aforementioned forum sites.

Please help me with the origin in the comment!

X sappin' mah Y

Also with the joke, there is a type of formula on this meme. Not just the Spy and the sentry, but with other enemys and objects. The formula goes something like this:

X(normaly a person, mostly the Spy) sappin' {my/mah} Y(a object)

Examples

"Spy sappin' mah computer."

"Billy Mays sappin' mah prices"

"Virus sappin' mah programs"

Other formula types

With the formula, it also gave birth to other forms of the original. For example:

Y sappin' mah X:

A switch of the X sappin' mah Y and make objects do the sappin'

Spy X(Verb) Mah Y:

Makes the spy do something that is not sappin' but something else. Alot of images point to sex jokes or "toilet humor"

MS paint spy

Also, strangely, a MS paint image of the blue Spy holding the electro sapper appeared around the internet, we don't know if it came from said phrase, but I don't think it has something to do with the meme.

On YTMND:

Spy Sappin Sentry

dammitdammitdammitdammit

Spread according to Google Insights

Even our former president is involved.