Friendly Monster:
⇩ ⇩ ⇦ ⇨ ⇧ ⇧ ⇨ ⇦ (DDLRUURL)
Infinite Stamina:
⇩ ⇦ ⇧ ⇦ ⇩ ⇨ ⇧ ⇨ (DLULDRUR)
Monster Always Chases:
⇧ ⇩ ⇧ ⇩ ⇦ ⇦ ⇨ ⇨ (UDUDLLRR)
99 Lives:
⇧ ⇧ ⇩ ⇩ ⇦ ⇨ ⇦ ⇨ (UUDDLRLR)
Only 1st two are useful.