Forerunner of the Heralds 

Creature — Merfolk Scout
When this creature enters, you may search your library for a Merfolk card, reveal it, then shuffle and put that card on top.
Whenever another Merfolk you control enters, put a +1/+1 counter on this creature.
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Cards that do something similar expected a card that isn't here?
Reports become test cases the matcher is graded against before an update ships. Delvefall isn't a chatbot guessing, it compares the printed rules text of every card with plain math, and examples like yours decide which differences should count.
Merrow Harbinger 100%
$2.89#9217
"When this creature enters, you may search your library for a Merfolk card, reveal it, then shuffle and put that card on top."
River Sneak 89%
$0.26#13631
"Whenever another Merfolk you control enters, this creature gets +1/+1 until end of turn."