@RIG  
My apologies. I should have tried to be clearer in my explanation. Whenever canon ponies appear in a different, already existent setting, be it film, game or any other, they have effectively been crossed over.
 
To quote an example from the guidelines _{(again, my apologies for the repetitiveness)}: “Rainbow Dash meeting Kamina (of Gurren Lagann) is a crossover; Rainbow Dash BEING Kamina is a crossover; Kamina as a pony is just ponification.”
 
Since this image has ponies appearing as characters from Starcraft (RD as a marine, TS as a Protoss and FS in place of Kerrigan), following the guidelines means it still counts as a crossover.

there is not a single starcraft character here, so is just a parody.

^i am confuse, first you said this is a crossover the you explain word by word why this is not a crossover.

^  
Well, no. “The ponified tag is for when characters who are normally human (or alien, or whatever) are rendered as ponies. If the only pony element is that the characters have been drawn as ponies, that’s not a crossover! It’s just ponified art. If they’re interacting with (or being) characters from the actual show as well, then it’s also a crossover.”

So, this is a ponification?

Don’t know if you’ll see this but still, with all due respect, RIG, but you may wish to re-read the guidelines. To quote: “The crossover tag is for when two settings collide somehow, and characters from one setting meet (or become) characters from another.”