When you encounter Chaotic Aether, each blank roll of the planar die is a roll until a player planeswalks away from a plane. (Then planeswalk away from this phenomenon.)

When you encounter Human–Time Lord Meta-Crisis, each player chooses one or two creatures they control. Each player creates a token that's a copy of the first creature they chose, except it isn't legendary. Then each player who chose a second creature puts a number of +1/+1 counters on the token they created equal to the power of the second creature they chose. (Then planeswalk away from this phenomenon.)

When you encounter Morphic Tide, each player shuffles all permanents they own into their library, then reveals that many cards from the top of their library. Each player puts all artifact, creature, land, and planeswalker cards revealed this way onto the battlefield, then does the same for enchantment cards, then puts all cards revealed this way that weren't put onto the battlefield on the bottom of their library in any order. (Then planeswalk away from this phenomenon.)

When you encounter Planewide Disaster, destroy all creatures. (Then planeswalk away from this phenomenon.)

When you encounter Spatial Merging, reveal cards from the top of your planar deck until you reveal two plane cards. Simultaneously planeswalk to both of them. Put all other cards revealed this way on the bottom of your planar deck in any order.

When you encounter Unleash the Flux, each player sacrifices a nonland permanent, then you flip a coin. If you lose the flip, repeat this process. (Then planeswalk away from this phenomenon.)