Open Question: If my lease says "no pets" what can my landlord actually do legally?

I signed a lease that is up in July, and all it says regarding animals is "no pets". It does not state any sort of repercussions (I have had prior leases that state specific repercussions of being caught with a pet). Anyway, I rescued a stray kitten. I have a new house I am moving into in May (I do not intend to break the lease-- I have the money to pay both rents) that allows cats. So I've got three weeks of illegal cat-having. Today I looked out the window to find my landlord's brother taking pictures of my cat through the window with his phone. Creepster-ish... but I'm sure it's legal. So anyway, I'm likely caught with this cat and I just want to know what the landlord can legally do to me now. Eviction? No problem, that gets me out of paying double rent, lol (or would I still be responsible for rent?). Can he keep my deposit, even if the cat has not ruined anything? I realize I've taken a risk here, and am willing to pay the consequences (sweet little kitty is worth it!), I'd just like to know what they are, legally speaking, before I get the awkward phone call. I live in Michigan, by the way. Thanks!