I love it when the series does the calcs for you. 
1. Supersonic
Maxwell can apply the adjective "supersonic" to himself and others.
scribblenauts.fandom.com
Or at least mach 1.
2. Hypersonic Philosoraptor
Maxwell creates a Hypersonic Philosoraptor. Hypersonic is at minimum mach 5. Easy.
Final Results
Supersonic adjective = Mach 1
Hypersonic Philosoraptor = Mach 5
1. Supersonic
Maxwell can apply the adjective "supersonic" to himself and others.
Supersonic
Supersonic is an adjective faster than fast. This adjective makes the wielder extremely fast when swimming and flying. In order to become as fast as possible in Scribblenauts Unlimited, one must apply this adjective to Maxwell along with Lightweight (which increases speed slightly and stacks...
scribblenauts.fandom.com Or at least mach 1.
2. Hypersonic Philosoraptor
Maxwell creates a Hypersonic Philosoraptor. Hypersonic is at minimum mach 5. Easy.
Final Results
Supersonic adjective = Mach 1
Hypersonic Philosoraptor = Mach 5
