New to Competitive play... How's my Defensive UU team?

Question

This is my team as follows.

Shuckle @ Leftovers
Ability: Contrary
Shiny: Yes
EVs: 4 HP / 252 Def / 252 SpD
Calm Nature
IVs: 0 Atk
- Rest
- Infestation
- Toxic
- Shell Smash

Blissey @ Leftovers
Ability: Natural Cure
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
- Wish
- Protect
- Seismic Toss
- Heal Bell

Beedrill-Mega @ Beedrillite
Ability: Adaptability
Shiny: Yes
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Poison Jab
- X-Scissor
- Toxic Spikes
- Swords Dance

Darmanitan (M) @ Air Balloon
Ability: Zen Mode
EVs: 4 HP / 252 Atk / 252 SpA
- Fire Punch
- Flamethrower
- Psychic
- Hammer Arm

Porygon2 @ Eviolite
Ability: Trace
Shiny: Yes
EVs: 252 HP / 120 Def / 136 SpD
Calm Nature
IVs: 0 Atk
- Recover
- Tri Attack
- Ice Beam
- Thunder Wave

Celebi @ Leftovers
Ability: Natural Cure
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Nasty Plot
- Giga Drain
- Psychic
- Dazzling Gleam

Thanks :)

Comments

Beedrill-Mega has no place in a defensive team with such miserable bulk. Use Forretress instead for laying down Spikes of all kinds. this frees your mega slot for something else. I may look into it in details later.