Maybe it's a very specific learning disability where commas are indistinguishable from periods.

BEAAAAAAAAARS

You... are naht like... deuddah bears.

This is not over! Bears!

DIS GUY . . . IS UN-FUCKING-BELIEVABLE

This is not over! I summon bears!

This is not over: BEARS

Just hearing him say this line without any visual context, you'd think he told a guy that this wasn't over and was then charged at by several bears.

A) This is not over.
B) BEARS!!

I'd buy a DvD of all of Walken's appearances in otherwise crappy movies like this. He was his usual awesome self in "Mousehunt," but the rest of the film was complete garbage.

THIMPLE: This is not over!!
.
.
(other stuff in the script Walken didn't like)
.
.
...Bears!!