Create Chimera

Upon completing the casting of this spell, you touch two beasts that have remained within range for the full casting time. The creatures must be living, and must not be above CR 1. If either creature is not a willing target of the spell, it must make a CON saving throw. If either creature passes the saving throw, the spell fails. A creature that is unconscious for the entire casting automatically fails its saving throw. 

Select which creature will be the base creature, and which will be the modifying creature it will inherit a trait from. If the two do not have a matching CR, the base creature must be the one with the highest CR. The base creature must be no more than a single size category smaller than the modifying creature. Upon completion of this spell, the modifying creature is merged into the base creature, and perceives through the base creature's senses, though it is incapacitated. The two can only be separated by Greater Restoration.

Next, select an ability score, movement speed, or sense from the modifying creature. The base creature permanently adopts the selected trait as it's own, replacing it's own ability score if one was selected. Its aesthetic changes, reflecting the influence of the modifying creature's form, and visual inspection of the creature reveals it has been magically altered. It gains any body parts necessary for using it's new traits, such as growing wings when gaining a flying speed, or a second set of eyes for acquired darkvision.

The base creature has the memories of the modifying creature, and will have it's opinions affected, but not overwritten, by them. The base creature maintains it's core values, though it may demonstrate personality traits of the modifying creature. This spell has no effect on the creature's opinion of the caster, though an unwilling creature may be distressed or violent immediately after casting.

Additional castings of this spell targeting an already modified creature will fail. You can, however, cast this spell with a previously modified creature as the sole target to change which trait from the modifying creature it is adopting.

At Higher Levels. When you cast this spell using a spell slot of 2nd or higher, the maximum CR for the targets goes up by 1 for each slot level above the first.