"Transient receptor potential vanilloid-1 (TRPV1) agonist; topical application causes initial TRPV1 stimulation that may cause pain, followed by pain relief by reduction in TRPV1-expressing nociceptive nerve endings"
Capsaicin
Ethacrynic acid
Ecstasy 
Naphthalene
Toxic alcohols
Strychnine
Monkeypox
N,N-Dimethyltryptamine