Simic Fluxmage

If the creature is an illegal target when Simic Fluxmage’s ability tries to resolve, it won’t resolve and none of its effects will happen. No counters will be removed from Simic Fluxmage.

To move a counter from one creature to another, the counter is removed from the first creature and placed on the second. Any abilities that care about a counter being placed on the second creature will apply.

If multiple creatures enter the battlefield at the same time, evolve may trigger multiple times, although the stat comparison will take place each time one of those abilities tries to resolve. For example, if you control a 2/2 creature with evolve and two 3/3 creatures enter the battlefield, evolve will trigger twice. The first ability will resolve and put a +1/+1 counter on the creature with evolve. When the second ability tries to resolve, neither the power nor the toughness of the new creature is greater than that of the creature with evolve, so that ability does nothing.