Adj. Rocktastic: A Portmanteau combination of two words "rock and fantastic" meaning beyond fantastic;or ridiculously wonderful; it is as long lasting as a rock or as exciting as rock n' roll with an extra dose of fantastic.
Rock~ rock is a naturally occurring aggregate of minerals and/or mineraloids.
Also, more importantly also refers to rock 'n' roll: a genre of popular music originating in the 1950s; a blend of black rhythm-and-blues with white country-and-western; "rock is a generic term for the range of styles that evolved out of rock'n'roll."
Fantastic~ antic: ludicrously odd; extraordinarily good or great ; used especially as intensifiers; fanciful and unrealistic; foolish;existing in fancy only;extravagantly fanciful in design, construction, appearance;is a literary term that describes a quality of other literary genres, and in some cases is used as a genre in and of itself, although in this case it is often conflated with the Supernatural; Existing in or constructed from fantasy; of or related to fantasy; fanciful; Not believable; implausible; seemingly only possible in fantasy; Wonderful; marvelous; excellent; extraordinarily good or great (used especially as an intensifier)
"Your outfit is so rocktastic. Everybody is going to love the way you look."
"This is an awesome show/concert were going to go see. We are sooo gonna have a rocktastic time."
"I just got a degree... resp: Congratulations! That is truly rocktastic."
"That fantasy or sci-fi movie, game, book, (insert some kind of entertainment or media) was fraken rocktastic."