Lonis, Genetics Expert is a rare Legendary Creature — Snake Elf Detective card from Ravnica: Clue Edition (CLU), collector number 37. Current market price: $5.39, TCGplayer market prices via Scryfall.
Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.) Whenever one or more +1/+1 counters are put on Lonis, investigate that many times. Whenever you sacrifice a Clue, put a +1/+1 counter on another target creature you control.