This guy was the best value creature in all of magic for a very long time
Remember, these cards care about how much mana you actually spent on the spell, not the printed mana value so the higher tiers of Ice Magic and Thunder Magic, the flashback casts of Dreams of Laguna and Laughing Mad, and a big Syncopate or Choco-Comet will all work to trigger your stuff
Besides +1/+1 counters, you've got plenty of ways to boost the power and toughness of your merfolk army , like Merfolk Mistbinder, Merfolk Sovereign, and Merrow Reejerey
It is still considered one of the most powerful cards ever and is banned or restricted in nearly every format
In fact, the cheapest copy of this card is its most recent printing from the Childs Play -themed Secret Lair Drop from 2024
If their mana value is more than three, they get three 1/1 counters