Shiinotic: Held Item. Big Root
Ability: Effect Spore
EVs: 170 Special Attack, 170 Special Defence, 170 Defence
Nature: Modest (for special attack boost) Or Timid (Gives you a boost in Speed and lowers Physical Attack)
A good move all round as it puts the enemy to sleep and has 100% accuracy.
Deals with Shiinotic's 4x weakness to Poison types and has good base power, complimenting Shiinotic's high Special Attack. Plus! The HP recovery is boosted by Big Root.
STAB boosted, HP recovery boosted by Big Root.
Hidden Power Rock.
Hits Reasonably hard with Shiinotic's base Special Attack. And it deals with all but 1 (Steel Type) of Shiinotic's remaining weaknesses
This is a more offensive set I created, it works rather well every time I've used it and can deal with pretty much everything thrown at it