I saw this commercial and thought exactly the same thing you thought. First I thought "What the fuck, how can you compare a leech to marijuana?" then I thought "If you're smoking because you're 'under the influence' then you're pretty fucking pathetic." Then I thought "That joint was so shittily rolled, I'm sure they could have gotten some stoner to roll it for the commercial instead of some dickweed that compares smoking weed to putting bloodsucking parasites on yourself to be cool."