Sheldon J. Plankton/appearances

Character

Gallery

Appearances

Bold means character played a Major role

Appearances = 88 episodes

Episodes

Season 1

1. Plankton! (debut)
2. Culture Shock
3. F.U.N.
4. Sleepy Time
5. Valentine's Day (cameo)
6. Walking Small

Season 2

1. Imitation Krabs
2. Christmas Who?
3. Welcome to the Chum Bucket
4. Band Geeks
5. The Fry Cook Games

Season 3

1. The Algae's Always Greener
2. Mermaid Man and Barnacle Boy IV (cameo at the ending)
3. Snowball Effect (cameo at beginning)
4. Krusty Krab Training Video
5. Party Pooper Pants
6. Plankton's Army
7. The Sponge Who Could Fly
8. SpongeBob Meets the Strangler (non-speaking cameo)

Season 4

1. Fear of a Krabby Patty
2. Krabs vs. Plankton
3. Dunces and Dragons
4. Enemy In-Law
5. Mermaid Man and Barnacle Boy VI: The Motion Picture
6. Patrick SmartPants (speaking cameo)
7. Wishing You Well
8. New Leaf
9. Best Frenemies

Season 5

1. Friend or Foe
2. Spy Buddies
3. Krabs à la Mode
4. Bucket Sweet Bucket
5. Goo Goo Gas
6. Atlantis SquarePantis
7. Mermaid Man vs. SpongeBob
8. Pest of the West (ancestor Dead Eye Plankton)
9. 20,000 Patties Under the Sea
10. Banned in Bikini Bottom
11. Stanley S. SquarePants (speaking cameo)

Season 6

1. Krabby Road
2. Spongicus
3. Patty Caper
4. Plankton's Regular
5. The Krabby Kronicle
6. Komputer Overload
7. No Hat for Pat (cameo)
8. Chum Bucket Supreme
9. Single Cell Anniversary
10. Truth or Square
11. Chum Caverns
12. Krusty Krushers? (cameo)

Season 7

1. Tentacle-Vision
2. Someone's in the Kitchen with Sandy
3. The Inside Job
4. Greasy Buffoons
5. SpongeBob's Last Stand
6. One Coarse Meal
7. The Play's the Thing (cameo)
8. Rodeo Daze
9. Gramma's Secret Recipe
10. The Main Drain
11. The Great Patty Caper
12. That Sinking Feeling (speaking cameo)
13. Buried in Time
14. Shellback Shenanigans
15. Perfect Chemistry

Season 8

1. Squidward's School for Grown-Ups (speaking cameo)
2. The Other Patty
3. Drive Thru
4. Frozen Face-Off
5. Sweet and Sour Squid
6. Plankton's Good Eye
7. Walking the Plankton
8. A SquarePants Family Vacation (cameo at the beginning)
9. The Krabby Patty That Ate Bikini Bottom
10. Fiasco!
11. Free Samples
12. For Here or to Go
13. Karen 2.0
14. The Good Krabby Name (speaking cameo)
15. Hello Bikini Bottom! (two speaking cameos)
16. Super Evil Aquatic Villain Team Up is Go!
17. Chum Fricassee
18. Move It or Lose It
19. It's a SpongeBob Christmas!

Season 9

1. Squirrel Record
2. Eek, An Urchin!
3. Plankton's Pet 
4. Evil Spatula
5. Jailbreak!
6. It Came From Goo Lagoon

Movies

1. The SpongeBob SquarePants Movie
2. The SpongeBob SquarePants Movie 2

Shorts

1. Plankton's Holiday Hits
2. Can't Swim
3. Remodeling
4. Loop dee Loop
5. Plankton Pays