Obstagoon

Despite its wild outward appearance, Obstagoon is not really worth raising in PvE. Its stats aren't great, it lacks a STAB fast move, and it falls like a house of cards against any Fighting Type coverage that the enemy may have up its sleeve. Its only real claim to fame is a triple resistance to Ghost, but even that doesn't make it an impressive choice.

Best PvE Offensive Moveset

• Lick, despite lacking STAB, can pair with Night Slash to let Obstagoon counter Psychic and Ghost Types
• Counter can pair with Cross Chop for a pseudo-fighting move, though it's not great in this role.
• Ignore Gunk Shot and Hyper Beam, they have no utility on offense for Obstagoon.
• Obstruct has pitiful damage output and is only meant for PvP.

Best PvE Defensive Moveset

• Counter is definitely stronger on defense, outclassing Lick by every meaningful metric.
• Night Slash has 3 bars, STAB, and very solid neutral coverage.
• Cross Chop is an okay choice, though it's definitely weaker here.
• Gunk Shot and Hyper Beam are far too slow on defense due to being 1-bar.
• Obstruct has pitiful damage output and is only meant for PvP.

Counter is one of the best fast moves in the game, and is superior to Lick in terms of damage output, energy generation, and coverage. 

Night Slash takes advantage of STAB to provide consistent damage, and has a small chance to boost Obstagoon's ATK. Cross Chop is sometimes underwhelming, but Obstagoon may need it to nail certain Fighting weak targets. Gunk Shot costs large amounts of energy, but is the only option available to threaten Obstagoon's weakness to Fairy-types. Hyper Beam demands enormous energy to use, but in return threatens significant neutral damage with STAB. 

Obstruct is a move limited to Community Day events and Elite TMs. It offers appealing utility on paper, buffing Obstagoon's DEF and reducing the opponent's DEF by 1 stage. However its damage output is pathetic, and with an energy cost of 40 and not the cheaper 35 tier, its performance is unfortunately not as impressive as we hoped. For more consistency and meaningful shield threat, it is recommended to use Night Slash paired with another secondary tech option, as Obstruct alone may not be adequate to deal sufficient Dark-type damage for Obstagoon's role, depending on the matchup. Obstruct's stat modifications can be very significant in drawn out matches, however.