Shadow Cradily

With a 20% boost to its attacking prowess, this barnacle outpaces titans such as and Shadow Bellsprout! And the Rock typing can potentially help against normal attacks such as Body Slam! Cradily never had much hope in PVE, and the Shadow Form isn’t much different. Numerous superior Grass and Rock types have been available, even in Generation 1. It’s probably best to use it in PVP, though even that's iffy.

Best PvE Offensive Moveset

• Bullet Seed is Cradily's only STAB fast move, making it the move of choice in most cases.
• Acid has better DPS and neutral coverage, while Infestation has higher energy gain.
• Grass Knot outperforms Stone Edge on neutral damage, but both have their matchups.
• Bulldoze serves no purpose on offense.

Best PvE Defensive Moveset

• Bullet Seed has the highest energy generation and damage with STAB. 
• Infestation ties with Bullet Seed's energy gains while being off-type with its best defensive charged move.
• Acid’s advantage is its neutral coverage, though it lacks STAB. 
• Grass Knot is strong and has 2 bars, which is appropriate for Shadow Cradily’s average bulk.
• Stone Edge is the most likely charge move to hit if Shadow Cradily manages to use it.
• Bulldoze is both weak and easily reactable.

Bullet Seed is Shadow Cradily’s best fast move, building energy pretty quickly and benefiting from STAB. Infestation offers the same energy generation, but falls behind slightly without STAB. 

Rock Tomb and Grass Knot benefit from STAB to provide very solid coverage, only being walled by Steel-types and certain dual-type Fighting Pokémon; Rock Tomb also provides an Attack debuff that further complements Shadow Cradily's wonderful bulk. Stone Edge is an very good move, but it's rather expensive, and Rock Slide is often preferred as a result. Bulldoze isn’t very good. Rock Slide is mediocre now that it has gotten a rather nasty nerf.