How many times can I activate this Lotleth Troll and Basking Rootwalla combo?
Without help from other cards, this combo will only work once; when you discard the Basking Rootwalla to put a +1/+1 counter on Lotleth Troll, and cast it for its madness cost, you'll end up with a Basking Rootwalla on the battlefield, so you can't discard it again unless you find a way to return it to your hand.