Got the same issue here:

15:24:01.476 INFO basemod.BaseMod> publish on Player Damaged
15:24:03.308 INFO basemod.BaseMod> publish on Player Lose Block
15:24:03.310 INFO basemod.BaseMod> publishPostEnergyRecharge
15:24:03.572 INFO basemod.BaseMod> publishPostDraw
15:24:03.772 INFO basemod.BaseMod> publishPostDraw
15:24:04.006 INFO basemod.BaseMod> publishPostDraw
15:24:04.237 INFO basemod.BaseMod> publishPostDraw
15:24:04.438 INFO basemod.BaseMod> publishPostDraw
15:24:18.572 INFO basemod.BaseMod> publish on card use: sneckomod:SnekBeam
15:24:18.572 INFO ThMod.ThMod> ThMod : Card used : sneckomod:SnekBeam ; cost : 1
15:24:19.172 INFO basemod.BaseMod> publishPostExhaust
15:24:20.504 INFO basemod.BaseMod> publish on card use: sneckomod:TailWhip
15:24:20.504 INFO ThMod.ThMod> ThMod : Card used : sneckomod:TailWhip ; cost : 2
15:24:20.872 INFO basemod.BaseMod> publish on post power apply
15:24:20.889 INFO basemod.BaseMod> powers modified
15:24:21.171 INFO basemod.BaseMod> publish on post power apply
15:24:21.181 INFO basemod.BaseMod> powers modified
15:24:24.972 INFO basemod.BaseMod> publishPreMonsterTurn
15:24:27.339 INFO basemod.BaseMod> publish on post power apply
15:24:27.346 INFO basemod.BaseMod> powers modified
15:24:29.242 INFO basemod.BaseMod> publish on Player Lose Block
15:24:29.242 INFO basemod.BaseMod> publishPostEnergyRecharge
15:24:29.305 INFO basemod.BaseMod> powers modified
15:24:29.604 INFO basemod.BaseMod> powers modified
15:24:30.572 INFO basemod.BaseMod> publishPostDraw
15:24:30.772 INFO basemod.BaseMod> publishPostDraw
15:24:31.005 INFO basemod.BaseMod> publishPostDraw
15:24:31.238 INFO basemod.BaseMod> publishPostDraw
15:24:31.472 INFO basemod.BaseMod> publishPostDraw
15:24:32.972 INFO basemod.BaseMod> publish on card use: sneckomod:Transmogrify
15:24:32.972 INFO ThMod.ThMod> ThMod : Card used : sneckomod:Transmogrify ; cost : 1
15:24:32.973 INFO core.CardCrawlGame> Exception occurred in CardCrawlGame render method!
15:24:32.974 ERROR core.CardCrawlGame> Exception caught
java.lang.IndexOutOfBoundsException: Index: 1, Size: 1
at java.util.ArrayList.rangeCheck(ArrayList.java:653) ~[?:1.8.0_144]
at java.util.ArrayList.get(ArrayList.java:429) ~[?:1.8.0_144]
at sneckomod.cards.Transmogrify.use(Transmogrify.java:102) ~[downfall.jar:?]
at com.megacrit.cardcrawl.characters.AbstractPlayer.useCard(AbstractPlayer.java:1698) ~[?:?]
at com.megacrit.cardcrawl.actions.GameActionManager.getNextAction(GameActionManager.java:358) ~[?:?]
at com.megacrit.cardcrawl.actions.GameActionManager.update(GameActionManager.java:175) ~[?:?]
at com.megacrit.cardcrawl.rooms.AbstractRoom.update(AbstractRoom.java:325) ~[?:?]
at com.megacrit.cardcrawl.dungeons.AbstractDungeon.update(AbstractDungeon.java:2532) ~[?:?]
at com.megacrit.cardcrawl.core.CardCrawlGame.update(CardCrawlGame.java:871) ~[?:?]
at com.megacrit.cardcrawl.core.CardCrawlGame.render(CardCrawlGame.java:419) [?:?]
at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:225) [?:?]
at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:126) [?:?]
Controllers: removed manager for application, 0 managers active
15:24:33.005 INFO core.CardCrawlGame> PAUSE()
15:24:33.006 INFO core.CardCrawlGame> Game shutting down...
15:24:33.007 INFO core.CardCrawlGame> Flushing saves to disk...
15:24:33.008 INFO helpers.FileSaver> Save thread interrupted!
15:24:33.009 INFO helpers.FileSaver> Save thread will die now.
15:24:33.011 INFO core.CardCrawlGame> Shutting down publisher integrations...
15:24:33.016 INFO core.CardCrawlGame> Flushing logs to disk. Clean shutdown successful.
Game crashed.
Cause:
java.lang.IndexOutOfBoundsException: Index: 1, Size: 1
at java.util.ArrayList.rangeCheck(ArrayList.java:653)
at java.util.ArrayList.get(ArrayList.java:429)
at sneckomod.cards.Transmogrify.use(Transmogrify.java:102)
at com.megacrit.cardcrawl.characters.AbstractPlayer.useCard(AbstractPlayer.java:1698)
at com.megacrit.cardcrawl.actions.GameActionManager.getNextAction(GameActionManager.java:358)
at com.megacrit.cardcrawl.actions.GameActionManager.update(GameActionManager.java:175)
at com.megacrit.cardcrawl.rooms.AbstractRoom.update(AbstractRoom.java:325)
at com.megacrit.cardcrawl.dungeons.AbstractDungeon.update(AbstractDungeon.java:2532)
at com.megacrit.cardcrawl.core.CardCrawlGame.update(CardCrawlGame.java:871)
at com.megacrit.cardcrawl.core.CardCrawlGame.render(CardCrawlGame.java:419)
at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:225)
at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:126)

This happens to me as well