Battle Moveset

A Good Moveset for Cradily would have to be this:

Attacks:

Toxic
Recover
Barrier/Amnesia or Mirror Coat/Earthquake/Rock Slide OR Hidden Power [Rock]/Giga Drain/Hidden Power [Fire]
Barrier/Amnesia or Mirror Coat/Earthquake/Rock Slide OR Hidden Power [Rock]/Giga Drain//Hidden Power [Fire]]

Items Attached:

Leftovers

Preferred Nature:

Bold

Strategy Using Cradily

Your basic Cradily. Toxic something then Recover-stall it and use whichever two moves you picked to back it up. Major downside to this set is the fact that Toxic sucks with all those clerics running around, as well as the unwelcome Steel and Poison types. You could give Hidden Power a try to surprise incoming Skarmorys who think its free switch-in time once they've seen Toxic, but you get nothing more than a crappy 3KO. Fortunately, praying for Critical Hits can pay off.

The most commonly seen Cradily's pack Barrier with Amnesia or Mirror Coat. With PHazers being more popular than Hazers and Cradily's trait, this can actual work. The downside is that you're still screwed if a cleric or Steel/Poison types comes out. Substitute will also tear you to pieces.

Giving Cradily some direct offence doesn't hurt hugely, since Cradily has the defences to survive without the aid of stat boosting. Earthquake scores super effectives on Steel and Poison types while Hidden Power [Fire] can have its way with Skarmory (the most commonly seen Steel type). Rock Slide/Hidden Power [Rock] and Giga Drain both gain STAB and have their own things that they can super effective against, and therefore should also be considered for use (although both are lacking in power with Cradily's low offensive stats).

Cradily does best with a lot of support. Getting rid of your opponent's cleric is always a must, as well as any Steel or Poison types and anything carrying natural cure.

EV Corner:

EVs: 222 HP / 88 Def / 200 SDef
Bold Nature (+Def, -Atk)

This is your base distribution. It'll need to be customised to whichever moves you are using.

With Mirror Coat: sacrifice Defence EVs for Special Defence.
With Barrier: remove all Defence boosts and place them into Special Defence and/or one of the offence stats, depending if you are using direct-damage attacks or not.
With Amnesia: remove all Special Defence boost and place them into Defence and/or one of the offence stats, depending if you are using direct-damage attacks or not

. If you choose to use direct damage attacks, boost their respective stats. Don't go overboard with it but anywhere between 200-220 should suffice. Sacrifice the defensive stats for this and maintain maximum Leftover recovery.

Other Optional Sets:

Cradily @ Leftovers
Trait: Suction Cups
EVs: 26 HP / 252 Atk / 232 Spd
Jolly Nature (+Spd, -SAtk)
- Earthquake
- Rock Slide
- Recover
- Sludge Bomb/Substitute/Mimic/Psych Up

This set works on the basis that you will be Baton Passing to Cradily. Due to its trait, Cradily is a perfect candidate for being on the other end of a Baton Pass from something like Ninjask or Smeargle. If you intend to pass two boosts for the speed stat, keep those EVs. If you only intend to pass one then add 8 more EVs so that it can outrun Max Speed Salamences etc. Two be truly effective this needs to be Baton Passed some form of Attack boost.

Sludge Bomb gets Grass types while Substitute is mostly a filler to prevent being Paralysed/Burned. Mimic is for stealing a good physical move from your opponent.

Psych Up is a little spin on the set that allows it to function on its own. Copy stat boosts from your opponent, such as Dragon Dances and Curses and then use them to your advantage.

Strategy Against Cradily

A nice Hazer or Psuedo-Psuedo-Hazer (something that forces switches by non-Roar/Whirlwind means, such as Yawn) will always be appreciated. The fact that this thing can't be PHazed is what leads to this thing carrying stat boosts so often. Ice Beamers and other special attacks should be weary of a potential Mirror Coat.

Steel and Fighting type attacks should be used against Cradily. Focus Punch can be easily set up since Cradily usually lacks the offensive power to break a Substitute and a STAB boosted Meteor Mash coming from Metagross will leave its mark on an unprepared Cradily.

The best method for handling Cradily is to use it to your advantage. Get a Substitute up and then start stat boosting. 9 out of 10 times you can do this successfully and you'll probably see Cradily switch out, leaving the switch in prone to whatever attacks you've got available. Things like Umbreon (assuming you had the sense to give it Taunt) will salivate at the opportunity Cradily gives, same for most other Baton Passers, just Umbreon especially since it can trap Cradily in play.

Contest Moveset

A good Contest Moveset for Cradily would have to be this for the Smart Contest best with Calm, Gentle, Careful, Sassy Nature:

Attacks:

Confuse Ray
Giga drain
Recover
Earthquake

Items Attached:

Green Scarf

Strategy Using Cradily

If you do the attacks in this following order you should have very few problems; 1st - Confuse Ray, 2nd - Giga drain, 3rd - Recover, 4th - Giga drain, 5th - Earthquake

Locations in Games

Ruby/Sapphire/Emerald Evolve Lileep Colosseum Trade from R/S/E Fire Red/Leaf Green Trade from R/S/E

Animé Appearences

Cradily has had an Animé Appearence. In it it was on an Island of Fossil Pokémon and scared Max Episode 379: Island of Dr. Morohoshi! Fossil Pokémon Appear!!