(nonstandard) Fantasticallyfun.But mom! Can't I go to the fair? The others say it will be funtastic!
1960, Eloise M. Jaeger & Harry Leighton, Teaching of Tennis: For School and Recreation Programs, Burgess Publishing (1960), page 58:The game becomes more "funtastic" if the teacher not only calls out the name of a line or space but adds a novel way of getting there or something novel to do once the players arrive at the designated line or space.
2005, Ruth Bushi, Dan Jones, & Anthony Leyton, The Push Guide to Which University 2006, Nelson Thomses (2005), ISBN 0748794891, page 336:Comedy: The comedy scene here is funtastic - check out Club Jongleurs and the Leicester Comedy Festival which is the biggest in Britain, attracting over 40,000 people a year.
2009, Sydney Salter, Jungle Crossing, Harcourt (2009), ISBN 9780152064341, pages 16-17:I turned thirteen the week after school got out (and had a slumber party that even Fiona called "oh-so funtastic").