NAH YOOZ AINT THINKEN BIG ENUFF, A CHOOPA DATS ATTCHED TO A BIGGA CHOOPA DATS ON FIRE, DAT SHOOTZ A ROKKIT DAT EXPLOADS INTA LOTS A LITTLE SQUIGS HAHA
So yeh take a rokkit, roight? Yeh open it up an' dump out all da 'splodey stuff (save it fer makin' stikkbombz later). Den, go into da squig pen, an' find yerself da sikkest squig youz can find. Get yer fingahz up 'iz noze, and scoop out all dat stikky stuff into dat rokkit shell from before. DO NOT ASK DA PAINBOYZ FER HELP! Prolly loze yerself an arm dat way. Anywayz, once yeh get yerself a few o' deez rokkitz filled up, now you gotz yerself a proppah weapon. Shoot it like a normal rokkit, but instead a' 'splodin, you gotz yerself a big ol puddle o' goo. Duzzint mattah wot goez thru, peeplez or weelz, it slowz down proppah, so you or yer boyz can dakka it ded. Even makez 'em a bit sikk til youz can line a shot up. I callz it....Da Booga Booga Launcha.
So maybe a Mekboy hears about dis 'melta' fad we've been seein and thinks, "that don't sound too hard", and gets workn'. What comes out is an old dakkajet engine strapped to a crucible fulla scrap, such that the scrap gets all heated and melty-like, and when da ork hits da big red button da engine overrevs and spits out a gob o' half molten metal (and de occasional half-molten grot). Bam. Ork Melty-gun!