At 6 mana, he’s probably too high on the mana curve to be relevant in Constructed. I imagine a Commander deck may be able to find room for him, but for the most part he’s just a big dumb beater. Hydras are very popular casual creatures, but there have been so many Hydras printed recently that give you tokens or additional value beyond just +1/+1 counters. Design-wise he’s sound, though, and very pickable if you’re leaning towards Aggro in draft. You just have to be either mono-Green or very heavy in Green to maximize this guy’s value, however, so he’s probably not a first pick.