The mosasaur is a prehistoric aquatic predator, similar in size and power to creatures like the orca or the great white shark.  Johann's version features advanced chameleon abilities, borrowed primarily from extant cuttlefish species.  While this form is unable to talk, its chameleon abilities allow fine enough detail to produce readable text (and, if need be, *glowing* readable text).

-1 echoes of the beast: precision chameleon - can use stealth in place of deceit for disguises - for example, appearing as a school of smaller fish, or some similar-sized species of shark or cetacean, or a giant squid (albeit with "tentacles" all streaming behind in a nice cylinder), or a submarine (complete with faintly glowing "portholes" and maybe some "sponsored advertisements").  As per normal disguise use, this will not hold up to intense scrutiny (i.e. if someone has the time and proximity to use investigation instead of alertness).
-1 claws
-0 big but subtle - has the physical mass for hulking size, but none of the modifiers
-4 supernatural strength
-4 supernatural toughness
+3 catch
-1 aquatic
+0 truly aquatic
-1 bioluminescent chameleon: can use stealth skill to hide underwater, even without anything to hide behind; this reduces penalties for lack of cover by two.
-1 cruising speed: +2 athletics when sprinting

(unspent: +1)
+6: fists, athletics
+5: might, endurance
+4: lore, stealth
+3: conviction, alertness, scholarship
+2: investigation, rapport, presence, discipline
+1: survival, empathy, deceit, performance

details on individual forms:
One each male and female forms; given Johann's addition of chameleon abilities, there's no need for more than that.