Chae's problem is that she's just plain incomplete. there's half a powerset and... nothing. that one isn't even a case of 'toss because it doesn't work' or 'toss because it's a joke' or the like. that one's just plain 'this isn't even an entry yet but a set of ideas.'
and hey, nobody expects their enemy to be an coaster. with every pokemon move in the game he can always use PROTECT and SUBSTITUTE to create a.... mini coaster in front of him. also to pre-empt an opponent who's attacking wildly he can go ME FIRST and bam, dead.
worst case, his substitutes run low and he goes RECOVER all his health back. he can also throw out a TOXIC and completely confuse the enemy as to what the hell is attacking them.
and you never expect a coaster to shoot a HYPER BEAM.
(there is a lot of fun in that character.)
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"Maybe it's a tentacle, molesting the planet itself. - Aschen Brodel.