Need Help Coding Punishment Card

[Terry Jones]

Feeling especially spiteful towards the current state of the meta, especially Link Summoning, would like to try and implement a monkey wrench....

Unfortunately I'm looking over the basic tutorials and I get the feeling this card idea is not covered in the basics. 

[Todes Skorpion]

Hey There :D
 

The concept is actually pretty cool as an anti-meta punishment card, but the issue is that Yu-Gi-Oh! doesn't really support "interrupting" a summon count the way this card is trying to do it. Right now your effect has a few problems:

1. It doesn’t specify when the effect activates.
2. It attempts to negate a summon after the summon procedure already started.
3. Link Summons don’t start a Chain, so you need wording similar to cards like Nibiru, Vanity’s Fiend, or Thunder King Rai-Oh.
4. “third special summon” tracking is difficult unless the card is already face-up on field.

The cleanest modern implementation would probably be something closer to this:
//If your opponent Special Summons a monster(s) for the 3rd time this turn (Quick Effect): You can Special Summon this card from your hand; negate that Summon, and if you do, banish that monster(s). While this card is face-up on the field, your opponent cannot Special Summon monsters from the Extra Deck the turn they activate a monster effect in the GY.//

Or if you REALLY want the “monkey wrench” feeling against Link combo decks
//Cannot be Normal Summoned/Set. Must be Special Summoned by its own effect.
If your opponent Special Summons 3 or more times in a turn: You can Special Summon this card from your hand or Deck.
While this card is face-up on the field, monsters used as Link Material are banished instead of being sent to the GY.//

That second version is much more realistic in modern PSCT and would genuinely hurt Link ladder decks without creating impossible rulings.
You want the card to either punish excessive summoning or alter the resource loop Link decks rely on.
Trying to directly “stop the third summon” gets very messy rules-wise.

Hope This helps :D
Great Idea :D