To say that Grok wasn't surprised wouldn't be true. However, he wasn't shocked that the cat wasn't what it seemed. This place oozed of evil and corruption. Deception often went hand in hand with the other two.
The thing had lashed out at him and caught him off-guard, causing the half-orc to become quite angry at the abomination.
OOC:
Heal and initiative rolls respectively
1d20+7=26, 1d20+1=8
Is this thing still the same size and general shape as a cat, but with black tentacles coming out of its body?