Wyo. Stat. § 4-10-403: Requirements for creation.

(a) A trust is created only if:

(i) The settlor has capacity to create a trust;

(ii) The settlor indicates an intention to create the trust;

(iii) The trust has a definite beneficiary or is:

(A) A charitable trust;

(B) A trust for the care of an animal, as provided in W.S. 4-10-409; or

(C) A trust for a noncharitable purpose, as provided in W.S. 4-10-410.

(iv) The trustee has duties to perform; and

(v) The same person is not the sole trustee and sole beneficiary.

(b) A beneficiary is definite if the beneficiary can be ascertained now or in the future, subject to W.S. 34-1-139.

(c) A power in a trustee, trust advisor, trust protector or other party designated in the trust instrument to select a beneficiary from an indefinite class is valid. If the power is not exercised within a reasonable time, the power fails and the property subject to the power passes to the persons who would have taken the property had the power not been conferred.