There is no indication anywhere in the game that this is how it works - and you can only fight him once, so if you miss the chance then you're out of luck
Note: This is a fan-made project with no official affiliation to OSRS or MTG
However, for those looking for a complete list of all twelve regular missions and the rewards that you'll get for completing them, the table below should be helpful
As soon as it does, even if it's on the first turn , your Pokemon will be cured
Release date: 2019-02-04 Zegana, Utopian Speaker Cloudfin Raptor Rapid Hybridization Cytoplast Root-Kin Experiment One Gyre Sage Miming Slime Vinelasher Kudzu Coiling Oracle Elusive Krasis Experiment Kraj Fathom Mage Momir Vig, Simic Visionary Nimbus Swimmer Omnibian Plaxcaster Frogling Progenitor Mimic Simic Sky Swallower Trygon Predator Urban Evolution Voidslime Vorel of the Hull Clade Zameck Guildmage Simic Signet Simic Growth Chamber Island Forest
Its randomness still needs to be accounted for, so you should only ever tutor creatures that youre okay with discarding