I first saw an altered version of this ad some time ago on a Vimeo channel "Slime Central", which had the Nickelodeon logo and some weird music edited in. The original ad I found only recently.
2) There was a discussion ( https://umd.net/forums/brunette-taking-slimed--random-internet ) about a behind-the-scenes footage from a commercial in which a woman (French model Marine Reed Brissonnet) gets splashed with green paint/slime, but the ad itself haven't been posted. I think that this Austrian T-Mobile commercial for their KLAX mobile phone SIM card is the original ad. Here it is on Vimeo, presumably uploaded by the production company that made it:
Also notice that the paint in the final commercial is pink (magenta) but in the making of video it was green. They must have filmed the ad with a "green-screen" paint and then changed the colour to magenta (T-Mobile's signiture colour) in post-production.