I just watched the clip, and as I suspected he doesn't say 'there is' as two separate words, he uses the contraction: there's. Technically, yes, it should be 'there are'. However in speech we make great use of contractions and "there're" is simply quite difficult to say (it doesn't even look very nice when written down), especially when talking at normal speed. It's much easier to use the 's' from 'there's' and roll it into the next word. It is very common to use 'there's' in front of a plural word, simply because it is easier to say.

Keep in mind here that we are looking at a character who might not speak with perfect grammar, such mistakes are common even with Native speakers. 

In terms of correct grammar, "there are lots of flavors" would be correct, but then when speaking about a list of singular items, "there is" is fine, so "there's Rocky Road, etc"